1. It is necessary for the student of architecture to have a good knowledge of the different kinds of stone, in order to decide which is best to use under any usual condition. It can hardly be expected that he will be able to determine the exact composition of a stone, but his knowledge should be sufficient to aid him in selecting or specifying stone best adapted to the purposes for which it is to be used, when the time comes to put the information thus gained to practical use.

The following paragraphs describe some of the principal building stones of this country, classed according to composition and structure.