Near all bodies of water, especially near old lakes, or the mouths of rivers, are forests under the surface, which show how ages ago trees grew where now nothing of the sort is found, or where other features of quite a different character exist on the surface. In Southern New Jersey quite a trade is done in wood of the white cedar, mined from many feet beneath the surface. In digging wells in Illinois, it is by no means uncommon to come on large trunks of Red Cedar, and New Orleans is over a complete Red Cedar forest, one hundred and sixty feet below the surface. According to Nature, a forest is also under the city of London. It tells us that an interesting geological discovery has been recently made during excavations for a new tidal basin at the Surrey Commercial Docks. On penetrating some six feet below the surface, the workmen everywhere came across a subterranean forest bed, consisting of peat with trunks of trees, for the most part still standing erect. All are of the species still inhabiting Britain: the oak, alder, and willow are apparently most abundant. The trees are not mineralized, but retain their vegetable character, except that they are thoroughly saturated with water.

In the peat are found large bones, which have been determined as those of the great fossil ox (Bos primogenius). Fresh-water shells are also found. No doubt is entertained that the bed thus exposed is a continuation of the old buried forest, of wide extent, which has on several recent occasions been brought to the day-light on both sides of the Thames, notably at Walthamstow in the year 1869, in excavating for the East London Waterworks; at Plumstead in 1862-3, in making the southern outfall sewer; and a few weeks since at Westminster, on the site of the new Aquarium and Winter Garden. In each instance the forest bed is found buried beneath the marsh clay, showing that the land has sunk below the tidal level since the forest flourished.