﻿xlii PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



collector is familiar with specimens of coniferous wood of the carbo- 

 niferous period, displaying characters most nearly allied to the living 

 Araucarise. Goppert indeed convinced himself that many of the seams 

 of coal examined by him in Germany, which have a structure like that 

 of charcoal, are derived entirely from coniferous timber, and Brong- 

 niart gives five genera and sixteen species of Coniferse of this epoch. 

 The Araucarian pines have large cones, and we may expect to meet 

 with the fruit of such trees hereafter, for Dr. Mantell tells me, he has 

 found between forty and fifty fossil fir-cones in the Wealden of Eng- 

 land, although not one is mentioned by Dunker, in his excellent 

 work on the Hanoverian Wealden. The coal-seams of this freshwater 

 deposit in Hanover, as I had an opportunity of attesting last summer, 

 are almost exclusively made up of the needle-shaped foliage of pines. 

 To prevent ourselves therefore from hazarding false generalizations^ 

 we must ever bear in mind the extreme scantiness of our present in- 

 formation respecting the flora of that peculiar class of stations towhich 

 in the palaeozoic era the coal-measures probably belonged. I have 

 stated elsewhere my conviction that the plants which produced coal 

 were not drifted from a distance, but nearly all of them grew on the 

 spots where they became fossil. They constituted the vegetation of 

 low regions, chiefly the deltas of large rivers, slightly elevated above 

 the level of the sea, and liable to be submerged beneath the waters of 

 an estuary or sea by the subsidence of the ground to the amount of 

 a few feet. That the areas where the carboniferous deposits accumu- 

 lated were low, is proved not only by the occasional association of marine 

 remains, but by the enormous thickness of strata of shale and sandstone 

 to which the seams of coal are subordinate. The coal-measures are 

 often thousands of feet and sometimes two or three miles in vertical 

 thickness, and they imply, that for an indefinite number of ages a 

 great body of water flowed continuously in one direction, carrying 

 down towards a given area the detritus of a large hydrographical 

 basin, draining some large islands or continents on the margins of 

 which the forests of the coal period grew. If this view be correct, 

 we can know little or nothing of the upland flora of the same sera, 

 still less of the contemporaneous plants of the mountainous or Alpine 

 regions. If so, this fact may go far to account for the apparent mo- 

 notony of the vegetation, although its uniform character may doubt- 

 less be in part owing to a greater uniformity of climate then prevail- 



