Of fossil sponges, palaozpongia and acanthosponffta and other forms occur in the Cambrian; and astyloapon gta, axtrcvospongia, palceomanon, etc, in the Silurian. Stro-matopora, which is placed in this class by some naturalists, occurs abundantly at the base of the Trenton, and in the Niagara group; and near the base of the lower Hel-derberg it forms a stratum four feet thick and extending over many miles. It is likewise abundant in the upper Helderberg and in the calcareous portion of the Chemung group. It is abundant in the Wenlock limestone of England. Other genera of sponges occur in carboniferous, Permian, triassic, Jurassic, cretaceous, and tertiary strata.
Organisms of this order are usually minute or microscopic. Some forms are known in the Cambrian and Silurian rocks of Europe. Ehrenberg has described species of textularta,rotalia, and guttulina from the greensands of the obolus or ungulite grits of Russia, which probably hold the same position as our Potsdam sandstone. In the carboniferous limestones of Ohio, Indiana. Illinois Iowa Missouri, and Kansas, rotalia. fusulina, etc are abundant, and probably other genera. The last named fossil forms layers of considerable thickness, known as fusulina limestone. The foraminifera are abundant in the Jurassic period, but acquire their greatest development in the latter part of the cretaceous and eocene tertiary in the mn,i-muhtes, orbitoides, orbitolina, etc. The nummulitic limestones are found in France and southern Europe northern Africa, and India, in the United States, and in the island of Jamaica. The most common form is seen in the limestone of the great pyramids of Egypt. Recepta-culitex, which is regarded by some naturalists as a gigantic foraminifer, is known in the Trenton group, and is abundant in the upper member of the formation, one species being a foot in diameter. It occurs also In the Niagara, lower Helderberg, and upper Helderberg formations.
The eozoön of the Laurentian has been referred to this order.
The graptolites are characteristic Cambrian and lower Silurian fossils, and most abundant on the confines of these two systems. Species of the several graptolitic genera range from the Potsdam sandstone to the Clinton group inclusive. Dictyonema. a graptolitic genus, is known from the base of the Trenton to the Hamilton group, or middle Devonian. Oldhamia, the oldest known fossil of the European Cambrian, is probably a graptolitic genus.
Of corals, the cyathophylloid type (order zoantharia rugosa) begin their existence in* the Cambrian, and are known from the base of the Trenton group, through all the formations, to the close of the palaeozoic era, acquiring their greatest development in the Devonian (cornif-erous and Hamilton). Corals of the same form, with different internal structure, known as the order zoantharia aporosa, characterize the formations from the trias to the present time. The latter are known as the neozoic, and the former as the palaeozoic type. Corals of the madrepore tribe (zoantharia tabvlata), as colvmnaria, farittella, fanoaites, etc, begin their existence about the same time 'as those of the cyathophylloid type, acquiring their greatest development in the Devonian, and disappearing at the end of the carboniferous period-Class ECHINODERMATA.
1. Crinoidea lenerinites. stone lilies).
2. Cystidea (cystideans).
3. Blastoidea (pentremites).
4. Atteriadoe (sea stars, star fish).
5. Ovhiuridai (sand stars, serpent stars).
6. Ediinidie and palechvinidoe (sea urchins).
7. Holoihuridm (sea cucumbers).
The encrinites are the earliest type of this class, and appear in the Cambrian system of Europe, and In rocks of the same age in America. The fossils of this family first become numerous in the Trenton period, and are abundant in the Niagara and lower Helderberg. They are usually not abundant in the Devonian, though the Hamilton group has yielded a considerable number of species: but they become extremely abundant in the carboniferous with the most extravagant forms in the lias, and from that time decline to the present epoch. The cystideans begin their existence at the same time as the encrinites, and are common in the Trenton and Niagara periods, gradually disappearing with the close of the Silurian age. The pentremites proper are of rare occurr* in the Silurian period, but become common in the Devonian, and reach their greatest development in the carboniferous, where they disappear. The star fishes are first knownin the Trenton period, and continue with increasing numbers through the Devonian and carboniferous epoch, and they occur in varied forms through the Jurassic, cretaceous', and tertiary, to the present time. '1 he ophiuroids (sand stars or serpent stars) begin their existence in the lower Silurian, and extend through the Devonian and carboniferous.
They are unknown in the Permian and triassic. but occur in the Jurassic, cretaceous, and tertiary and are more numerous in the modern seas. The echi-noids, of the type otpalechinus or eoctdarte, commence in the Devonian period and continue through the carboniferous The true echinidce and cidaridec begin in the lias and continue to the present time. The holothurians, which are soft, cylindrical bodies, are found in the lias, being recognized from certain minute calcareous parts known to belong to this order of echinoderms.
The fossils of this class of shells first appear, as representatives of the families nuculidoe and arcadce, in the Cambrian period, and are known in the Quebec group and Trenton limestone, in the genera tellinomya, niuiulites,&nApalm-area; and the arieulidiv and rnytilidoe are represented in the Trenton period. They gradually increase in numbers through the Silurian strata, until in the Devonian (the Hamilton and Chemung groups) these fossils, in the genera aviculopecten, ptertnea, nucula, nuculites. gram-mysia, etc, are sometimes more numerous than the bra-chiopoda. In later times the shells of this class acquire a much greater importance, and largely preponderate over the brra chiopoda.
The fossils of this class began their existence in the earliest geological periods, and we recognize them in the Potsdam sandstone of America and the Cambrian of Kurope. The earlier forms belong to the families turbinidoe, haliotidoe. ailyptrceidoe, bellerophontidoe, atlantidoe, etc. Maclurea, ophileta, and euomphalus occur in the calciferous sandstone.
The fossils of this class commence in the lowest fossiliferous strata. The genus theca occurs in the Potsdam sandstone. Pterotheca and conularia are found in the Trenton limestone, and the latter continues through the Silurian, Devonian, and carboniferous periods.
The fossils of this class have existed in all geological ages, and appear in varied and conspicuous forms. The oldest known in the Cambrian system are orthoceratites, of which we have great numbers in the Black river and Trenton limestones. Associated with these are lituites and cyrtoceras, which continue to the Devonian period. The genus goniatites begins in the Devonian and continues through the carboniferous. In the triussic begin the genera ceratites and ammonites; the latter appear in great numbers and variety of form in the Jurassic period, and still continue, together with seuphites turrilites, and baculites, in the cretaceous system, beyond which these forms do not occur. The genus nautilus appears in the Silurian, and continues through all the geological periods to the present time.
These are bodies consisting mainly of branching or reticulated calcareous fronds, rising from a root, or of expansions adhering to other bodies, minutely celluliferous. The most common palaeozoic forms are fenetstella, retepora, polypora, etc. In America these fossils reach their maximum development in the carboniferous period, where the spreading fronds are sustained by a strong central axis, upon which they grow in a spiral arrangement, as in the genus Archimedes.
The fossils of this class are everywhere abundant, and are the best guides in the study of the strata throughout the palaeozoic period. The linguloid type, in the genera lingulellaand lingulepis, begins in the lowest known fossiliferous formation, and continues through every geological epoch to the present time. The genus obolus characterizes the oldest Cambrian beds of Europe and the Potsdam of America. The orthidoe, in the genera orthis and orthisina, begin in the Cambrian, become more abundant in the Silurian, and. gradually lessening, die out at the end of the carboniferous period. The same is true of the stropfiomenidoe, represented in the genera stropho-mena. leptaena, strophodonta, and streptorhynchns. The rhytichonellidce begin in the Chazy limestone, and continue throughout all the geological periods. They are especially abundant in the upper Silurian, Devonian, and carboniferous periods. The spiriferidoe, in zygospira, begin in the Trenton formation, and characterize the Clinton and Niagara groups in the genera spirifera, cyrtia, cyrtrena, and meristella. The genus athyris begins in the Devonian, and the family dies out in the genus spiriferina in the Jurassic period.
The pentameroid forms begin in the Trenton and disappear in the Devonian. The family productidix, appears in the genus chonetes at the period of the Clinton group, and continues through the carboniferous. Productus (produclella) begins in the upper Hel-derberg, continues through the carboniferous, and disap.
* The hrarhiopnda are placed in this connection without expressing any opinion regarding their relations. That they are not true mollusca seems very clear from the condition of the fossil forms, the structure of the shell, and the character of the muscular and vascular impressions, as well as other reasons but it may be premature to insist on their arrangement with the pears in the Permian. The discinidoe, in the genera discina, trematis, etc, begin their existence in the Trenton and Hudson river periods, and are represented by discina, orbiculoidea, and allied forms, through the Devonian and carboniferous periods, and to the end of the geological series. In like manner the craniadoe begin as low as the Trenton and extend through the entire series. The terebratulidoe are first represented in the upper Silurian of the lower Helderberg, and are thence known in the genera cryptonella, centronella, terebratula, terebra-tella, Waldheimia, etc, to the end of the series.
The forms of this class have no solid shell, the soft parts being protected by an elastic gelatinous covering having two orifices. The soft character of these organisms precludes their preservation in the rocky strata.
The tracks of animals of this class (or perhaps of crustaceans) are found in the Potsdam sandstone of America, and in the Cambrian rocks of Europe. The order tubicola is represented in the lower strata by serpuloid forms. Arenicolites, or worm burrows, are common in the oldest fossiliferous rocks; so that this class of organisms has existed from the most ancient times.
The entomostraca in the order trilo-bita is represented in numerous genera, beginning in the lower Cambrian rocks, extending through the Silurian and Devonian; gradually lessening in the latter, and dying out entirely in the carboniferous period. The order merostomata, represented in the genera eurypterus, pterygotus, slimonia, dolichoptervs, stylonema, and arthropleura, begin their existence in the middle Silurian, and extend in some variety of form to the close of the coal measures. The phyllopoda commence near the base of the Silurian proper, and appear in the palaeozoic rocks in the genera ceratiocaris, dithyrocaris, and others. The ostracoda or cyproidea, in the form of small bivalved crustaceans of the genera primitia, leper-ditia, cytherina, Beyrichia, bolbozoa, aristozoa, etc, occur in the lowest fossiliferous rocks, and continue through the palaeozoic age; these are followed in later periods by cythera, cypris, cyprella, cypridella, etc. The podophthalmia or decapoda, including the crabs, lobsters, and their allies, commence their existence after the palaeozoic era, and continue through all the formations to the present time.
The cirripedia begin as low as the Trenton limestone, in the form of plumulites or turrile-pas; continuing but sparsely below the carboniferous, where they become more common, and increase in number of forms through the succeeding epochs to the present.
Fossil spiders are found in the carboniferous strata, in the Solenhofen slates of the Jurassic, and in the tertiary.
Centipedes and millipedes begin their existence in the carboniferous period.
Fossil remains of insects have been found in the lower coal measures and in the Devonian, and more abundantly in the lias limestone of Europe. In some portions of the tertiary formation of the western territories their remains are abundant, and also in the tertiary of Europe.
The ganoids, an order covered with bony plates, like the garpike and sturgeon, are among the earliest known forms of fishes. The genera coccosieus, pterichthys, onychodus, macropetalichthys, etc, occur in the upper Helderberg, lower Devonian, and subsequent formations. The genera cepha/aspisand lioloptychius are known in the old red sandstone of Europe, and the remains of the latter genus abound in the Catskill formation of New York and Pennsylvania. The genera eurytepis, coelacanl/n/s, and others are known in the coal measures of Ohio. Of the selachians, or fishes with cartilaginous skeletons, the eestracionts begin their existence in the age of the upper Helderberg, and continue through all the formations to the present time. The hybodonts first appear in the lower carboniferous, and continue through succeeding formations. The raiidce (rays) begin their existence in the carboniferous, and are known in the lias and eocene formations, and in the present fauna. The squalodonts, or true sharks, first appear in the cretaceous period, and continue to the present time. The teliostei, or bony fishes, such as perch, cod, salmon, etc, commenced in the trias. Some forms occur in the middle and upper Jurassic, but are not common below the cretaceous period.
No fossil fishes are known in the Silurian of America; and it may be considered doubtful if the European species cited as Silurian are really older than our own.
The order labyrinthod onta is represented in the carboniferous period of Europe and America. The apateon and archegosaurus are European forms; amphibamus, raniceps, dendrerpeton, hylono-mm, baphetea, and sauropm are found in the coal measures of Nova Scotia and the United States. Footprints of labyrinthodonts are known in the coal measures of Pennsylvania. Illinois, Indiana, and Kansas. The genus lepi-dotomurm is known in two species in the Permian of Europe. The labyrinthodon (cheirotherimn), anisopus, otozoum, macropteria, telerpeton, and other amphibians occur in the trias.
The order lacertia is represented in the Permian by the genera prolorosaurus, palwosaurus, deuterosaurus, and thecodontosaurus; the last is one of the most highly organized forms of the order. The genera rhynchosaurus, clepsysaurus, belodon, phytosaurus, rhabdopelix, and others, are characteristic of the trias of Europe and America. Other genera are known in the Jurassic and cretaceous, and in the present period. The genus mosasaurus, beginning in the cretaceous, is most conspicuous among the saurians of that period, occurring in numerous localities and in many species. Of the order crocodilia, the genera teleosaurus, hyposaurus, thora-cosaurus, ho/ops, and mystriosaurus are examples. The order begins in the trias, and continues to the present time, the true crocodiles occurring in the tertiary. The order pterosauria (flying saurians) are represented by the genera pterodactylus, rhamphorhynehm, and orni-thopterus, beginning in the lius and disappearing with the cretaceous. The order dinomuria, represented by the genera iguanodon, megalosaurus, anomoypus, bathygna-thus (an amphibian'/), hadrosaurus, hyloeosavrvs, and others, begin their existence in the trias, and continue to the base of the cretaceous period in Europe and America. The order dicyiiodonla is a remarkable group of saurians, represented by dicynodon, ouedenodon, and others, in supposed triassic rocks of south Africa and Bengal. The enaliosaurians (sea lizards), including plesiosaura and ichthyosaura, began their existence in the trias, disappearing with the cretaceous.
The genera nothosaurus, limosaurus, and sphenosaunis are among the triassic forms; and ichthyosaurus and plesiosnurus are characteristic liassic forms, occurring also in cretaceous. To the same order belong the discosaurus and polycoteles of the American cretaceous. The ophidia (serpents) make their first appearance in the eocene tertiary, and continue in all the more modern epochs. The genu's palceophis is characteristic of European and American tertiary; and lithophis, limnophis, and dinophis have been described from American tertiary. The chelonia (turtles, tortoises) begin their existence in the middle of the Jurassic period, and continue to the present time. The earliest forms were of marine habitat, but at later periods we find freshwater and land forms. The tretosternum is the earliest well established genus. A monstrous form, atlantochelys, and other large and small turtles, occur in the cretaceous of Kansas. The genera trionyx, emys, compremys, colos-sochelys, and others occur in the tertiary.
The existence of birds has been inferred from the occurrence of three-toed tracks in the sandstone of the Connecticut valley of the age of the trias (?). A remarkable genus of bird's, the archceopteryx, has been found in the Jurassic slates of Solenhofen. The genera termator-nis, paloeeotringa, laornis, ichthyornis, apatornis, and others, have been described from the cretaceous. Fossil birds occur in the Wealden of Europe, and numerous genera and species in the tertiary of Europe and America. The miocene beds of France afford more than 70 species.
The marwpialia were the first in geological order among the mammalia, the genus microlestes occurring in the upper trias of Germany and England. The dromatherium sylvestre of Emmons is a small marsupial animal from the trias of North Carolina. The spalacotherium, amphitherium, and phascolotherhnn have been found in beds of the Jurassic age; while other forms are known in the tertiary. The cetacea appear in the American eocene period in the gigantic genus zeuglo-don. Other forms occur in the miocene of the Atlantic coast; and the skeleton of a small whale, beluga, has been found in the post-pliocene of the Champlain valley. Of the order ungulata. the palaotherium, anapilotherium (xiphodon), and lophiodon were the earliest representatives in the eocene of Europe; and in the same formation in America, we have the genera hyrachyus and pahvo-syops. belonging to the same group as the preceding; the mtitatherium and dinoceras. which belong to the rhino-cerata; and the orohippus of the equidoe. In the miocene we have the genera anchitherium, hipparion titan otherium,rhinoceras. oreodon. brontotherium, and others. The horse, camel, llama, deer, musk ox. hog, tapir, hippopotamus, and other forms are represented in that epoch, and are continued to the present time.
The genus bos occurs only in the latest tertiary or quaternary. Of the proboscidce, we have the dinotherium, mastodon, and elephas in the upper miocene; but the elephant and mastodon are more characteristic of the pliocene and later formations. The camivora begin their existence in the tertiary. Among the earliest forms are arctocyon and palceocyon in the eocene; the genera hyaenodon mn-cfuerodus, fells, canis, cyjiodon, amphicyon, ursus hyoena. and others, occur in the later epochs of tin- Bys-tem. Of the rodentia. the genera arctomys, lepus, mm castor, arricola, lagomys. and others, occur in the later tertiary. The cheiroptera, or bat-like animals, begin their existence in the later tertiary; as also the insec-tivora proper, none of them appearing before the later miocene.
The following synopsis of the classification of plants will serve for general reference in palaeontology:
Class I. Anopiiytes, and II. Thallopuytes or cellular cryptogams. Musci, hepaticte, lichens, fungi, algoe, detmideoe. Class III. Acrogens. or vascular cryptogams.
Equisetaceoe, filices, lycopodiaceoe, hydropteridoe.
Class IV. Endogens or Monocotyledons.
The orders of this class include the cyperaceoe (sedge). gramineoe(gr&ssee),juncaceoe(bulrushes),liliacea (lilies), typhaceoe (cattail), palmacece (palms), and many others. Class V. Kxogens or Dicotyledons.
Under the subclass of angiospermous plants (seeds In a ericarp) are included more than 100 orders, which em-race all the ordinary forest trees except the coniferoe, besides far the greater proportion of flowering plants. Under the subclass of gymnosperms (seeds naked) are included all the coniferoe.
Until near the end of the Silurian period, the only remains of plants are of marine origin, such as algoe or fucaceoe; while some of the forms classed as plants may be really sponges. The earliest evidence of dry-land vegetation began with those conditions which ushered in the Devonian epoch; for the general character of the flora in the Devonian of America, so far as known, remains essentially the same throughout the carboniferous period. Here we have land plants of acrogenous forms, such as ferns in great abundance; the equiseta-ccce in the calamities; the lycoporiiurcai in the lycopodites, lepidodendron, &c; while psaro-nius, stigmaria, sigillaria, and others constitute orders allied to those mentioned. During this period the phenogamous plants are comparatively rare, and these are of the coniferoe. The condition of the surface favored only the development of the lower orders of vegetation; and we know that the low land of this period was subject to the influx of the ocean, probably from oscillations of the continental land, giving alternate strata of land deposits with land plants, and marine calcareous strata with shells and marine remains alone.
The great amount of land vegetation at this period does not indicate that the entire surface of the present continent was then dry land, and that plants everywhere abounded at the same time and are imbedded in strata of this age. On the contrary, at the west and southwest, land plants are extremely rare, or altogether wanting in rocks of this period; while strata of marine origin with marine animal remains hold the same position. At each successive geological period the flora appears to have approached more nearly that of the present; not however in the same latitudes, for the older floras of the temperate zones exhibit in many respects a tropical aspect. In the cretaceous and tertiary periods, the flora embraces many genera of the existing flora of the temperate zones. In the successive faunas also, even of the ocean bed, we are to take into consideration the existing physical conditions. In the very early periods coarse and fine sediments are found, indicating, if not shore lines, at least shallow and disturbed water on one side, and deeper seas with quiet water and finer sediments on the other.
The geographical extension of species does not always correspond with the nature of the sediments; for while in the Trenton period we have a large number of brachiopoda extending over wide areas, even as far west as the formation is known, the same is not true of the Hamilton group, although the physical characters of the two formations appear to have been equally uniform. This fact, however, does not furnish an argument in favor of gradual climatic or other permanent changes; for again in the carboniferous period certain forms of brachiopoda have even a wider range than in any preceding period. - The causes affecting the distribution of the faunas and floras of the several geological periods cannot be discussed in a sketch like the present; but that these have successively appeared and disappeared is ascertained in every part of the habitable globe. Of the succession or coming in of new species we have everywhere abundant evidence; and in a great proportion of instances they could not have been derived from sources very far from where we find their imbedded exuviae.
TABULAR ARRANGEMENT OF THE GEOLOGICAL FORMATIONS, WITH THE NAMES OF SOME OF
THE CHARACTERISTIC ORGANIC REMAINS.
MODERN or QUATERNARY.
Recent and post-pliocene.
Alluvial deposits, peat, calcareous tufa, glacial and modified gravel, with remains of man; associated plants together with extinct fossil mammalia - elephas, mastodon, megatherium, mylodon, glyptodon, &c; with shells, etc.
CENOZOIC or TERTIARY.
Mostly marine shells, bivalves and univalves in great numbers, and largely of living forms. The fossil flora indicating a warmer climate than the present.
The upper part with some extinct mammalian remains, elephas, mastodon, sivaiherium, hexaprotodon. The fossil flora contains species of acer. platanus, smilax, etc. The marine fauna with a mixture of extinct and existing species (India). The lower miocene has a greater proportion of extinct forms, and is remarkable for its great number of extinct mammalian remains, especially in the western part of this continent among which are rhinoceros, oreodon, bronlotherium, titanotherium, palceotherium, anchitherium, archaotherium, machwrodus, etc.
In the upper part, land and fresh-water shells, with mammalian remains; marine shells, corals, foraminifera. Many remains of sharks of enormous size. Cetaceans (whales, zeuglodon, &c), herbivores, carnivores, ruminants, pachyderms, monkeys, etc, first appear.
MESOZOIC or SECONDARY.
Upper cretaceous (Maestricht chalk, white chalk, and chalk marl).
Characterized by remarkable forms of saurians of several genera, mosasau-rus, etc, chambered shells (ammonites), univalve and bivalve shells, echinoderms, and corals; brachiopoda. mostly rhynchonellidce and iere-bratulidw; and the remarkable family rudistes; and in America by a fossil flora analogous to the tertiary anil recent forms, as maple, willow, beech, poplar, elm, sassafras, etc.
Lower cretaceous or
Many cephalopods. including amrnonitoid shells in a great variety of forms, with many peculiar forms of bivalve mollusca, as well as the ordinary forms. Fishes allied to the garpike. A remarkable fresh-water saurian (iguanodon). The flora is characterized by a great number of coniferoe, cycadeoe, and ferns. First appearance of deciduous trees. Bony fishes (teliosts) become common; crocodiles and cetaceans (whales).
Marsupial and insectivorous mammalia - ampMtherium, pliascolotherium. A remarkable form of bird, archoeopteryx. Flying reptiles (pterodactyls). Large numbers of fishes, insects, crustaceans resembling the common crawfish, chambered shells (ammonites, belemnites, &c) univalve and bivalve shells. Brachiopoda. echinideae. crinoidea, corals. etc. Among the fossil plants the cyeadeoe predominate (zamia being the prevailing genus), with coniferas and ferns.
Lias (limestones and slates).
The lower (liassic) beds are characterized by remains of gigantic saurians, ichthyosaurus, pterosaurus, etc.; fishes of the shark family and others; insects, with mollusks of the several orders, and extravagant forms of crinoidea, etc.
Upper, middle, and lower trias. Red sandstones of Connecticut valley.
Shales, sandstones, and beds of bituminous coal.
Mollusca numerous; the cephalopods chiefly of the genera ceratites, ammonites, and orthoceras, the latter genus becoming extinct in this formation. Last appearance of the brachiopodous family spiriferidoe. One form of encrinite abundant. Fish teeth and saurian remains. A remarkable batrachian form, the labyrinthodon. First appearance of mammalian remains in microlestes and dromatherium. Tracks of saurians and birds (?) both in Europe and America. First appearance of crawfish-like crustaceans. A remarkable coal field near Richmond, Va., with an abundant fossil flora. All classes of the vertebrata, viz., fishes both of the cartilaginous and bony forms, reptiles, amphibia, birds, and mammals, are represented in this epoch.
TABULAE ARRANGEMENT OF THE GEOLOGICAL FORMATIONS (continued).
Upper Permian. Middle Permian, or Magnesian limestone. Lower Permian.
Sometimes regarded as a group of passage beds from the coal measure to the triassic. Molluscan fauna not abundant. Brachiopoda, Borne of which are common to the carboniferous. Last appearance of the genus pro-ductus. Bryozoa abundant. Fossil fishes mostly of genera common to the carboniferous. The flora is mainly peculiar to the group, but some species are common to this and the coal measures.
Coal measures and upper limestones.
Upper carboniferous limestones and shales.
Upper and low'r coal measures.
Red shales, etc, at base.
Bryozoa and brachiopoda abundant, lamellibranchiata common : some corals, echinidese, crinoidea, cephalopoda. First appearance of batrachian reptiles and air-breathing mollusca, insects, scorpions, and shrimp-like crustaceans; and last appearance of trilobites. Ganoid fishes numerous. Land plants, as tree ferns, sigillaria, stigmaria, catamites, ic.
Lower carboniferous limestones.
Chester or Kaskaskia limestone.
St. Louis limestone.
Corals not abundant. Bryozoa abundant in the upper members. Brachiopoda abundant. Mollusca common throughout. Crinoidea extremely abundant. Echinoidea and blastoidea very abundant, the latter more common in the upper members, which contain fewer crinoidea. Cestra-ciont fishes abundant. (Formation calcareous).
Waverley group. Conglomerates.
Sandstones, shales, and limestones in thin beds.
Brachiopoda and lamellibranchiata, bryozoa. crinoidea. Fish remains. Fossil ferns. Marine plants of the genus dictyophyton. Land plants of the genera sigillaria, lepidodendron, catamites, etc.
Catskill group. Conglomerates. Sandstones.
Red, green, and olive shales and sandstones.
Remains of ganoid fishes (holoptychius) abundant, with fucoids and many land plants, as ferns, etc.
Chemung group. Sandstones, 6hales, and conglomerate. Limestone in the west.
Fucoids and land plants. Lamellibranchiate shells and brachiopods abundant. Gasteropods, cephalopoda, and crustaceans rare. Crinoidea and bryozoa not common. Eemains of cestraciont fishes. In the calcareous beds of the western extension are many corals, stromatopora, brachiopods, &.C.
Portage group. Shales and sandstones.
Fucoids and land plants; crinoidea. Lamellibranchiata and brachiopoda rare. Cephalopoda (goniatites) common. Fish remains of remarkable forms, belonging to the genera dinichthys, aspidichthys, ctenacanthus, etc.
Hamilton group. Shales, calcareous shales, limestones, etc.
Fucoids (spirophyton) and land plants abundant in certain beds. Lamellibranchiata and brachiopoda abundant. Gasteropoda and cephalopoda common. Crustacea, crinoidea, and corals abundant.
Corals, brvozoa, and brachiopoda abundant. Gasteropoda and lamellibranchiata common. Among the cephalopoda the genus goniatites is first noticed. Crustacea (trilobites of extravagant forms) common. Teeth, body plates, and spines of fishes, mostly cestracionts, appear for the first time, some of them of very ponderous dimensions. Macro-petalichthys, onychodus, etc. Land plants make their first appearance, with the exception of upper Silurian (?) in Nova Scotia.
Fossils extremely rare. Some marine plants (spirophyton).
Brachiopoda abundant and of remarkable forms. Gasteropoda abundant. Lamellibranchiata and crinoidea few.
Lower Helderberg group. Upper pentamerus limestone. Shaly limestone. Pentamerus limestone. Tentaculite limestone.
Corals and bryozoa. Brachiopoda and gasteropoda abundant. Crinoidea, cystidea, and Crustacea common. Lamellibranchiata and cephalopoda few. Petrospongia, etc.
Crustacea of the genera eurypterus, pterygotus, ceratiocaris, Ac.
Onondaga or Salina formation.
Magnesian and argillaceous limestones.
Red, gray, and greenish marls.
The formation essentially non-fossiliferous.
Sponges, corals, bryozoa, crinoidea. brachiopoda, and cmstacea abundant. Cephalopoda common. Lamellibranchiata and gasteropoda few.
Marine plants abundant. Bryozoa. graptolitcs, brachiopoda. a few lamellibranchiata. gasteropoda, cephalopoda, Crustacea, and crinoidea.
Anticosti group, island of An-ticosti. representing the Clinton and Medina groups.
Highly fossiliferous in brachiopoda and mollusca, with bryozoa. corals, and Crustacea.
TABULAR ARRANGEMENT OP THE GEOLOGICAL FORMATIONS (continued).
UPPER CAMBRIAN (Sedg.), or
LOWER SILURIAN (Mur.).
Shawangunk or Oneida conglomerate.
Non-fossiliferous limit between Silurian and Cambrian systems.
Hudson river group. Sandstone and stales. Calcareous shales. Do. and limestones. Utica slate.
Marine plants, graptolites, crinoidea, bryozoa, and brachiopoda abundant. True corals few. Lamellibranchiata in some localities abundant. Gasteropoda, cephalopoda, and Crustacea common.
Trenton group. Trenton and Galena, Black river, and Birdseye limestones.
Marine plants, crinoidea, cystidea, bryozoa, brachiopoda. Cephalopoda (orthoeeras) and Crustacea abundant. Lamellibranchiata and gasteropoda common. Corals few.
Taconic system of Emmons.
(Quebec group of Logan.) Chazy limestones. Levis shales and sandstones. Crystalline limest's (marbles). Dolomitic conglomerate. Calciferous sandstone.
Graptolites, crinoidea, and cystidea. Brachiopoda. Some mollusca and many trilobites.
Graptolites. Crustacea (trilobites) abundant. Brachiopoda in linguloid and oboloid forms abundant.
Sandstones, slates, etc. Braintree, Mass., St. John, N. B., and Newfoundland.
Crustacea. Genus paradoxides and other primordial forms.
Crustacea in numerous trilobites of the genera paradoxides, conocoryphe, agnostus, and others.
Sandstones, conglomerates, shales, and limestones. Specular iron ores.
Crystalline and subcrystalline; non-fossiliferous so far as known.
Labradoritic rock. Crystalline limestones. Gneiss in great variety, with iron ores.
Highly crystalline, and for the most part non-fossiliferous. The serpentine limestones contain the fossil called eozoon, the organic nature of which i.» advocated by some and disputed by others.