728 



been pressed the geological history alike of animal and vegetable 

 organisms. 



" It is not much more than twenty years since it was held that no 

 exogenous plant existed during the carboniferous period. The fre- 

 quent occurrence of Coniferae in the secondary deposits had been 

 conclusively determined from numerous specimens; but, founding on 

 what seemed a large amount of negative evidence, it was concluded 

 that, previous to the liasic age, Nature had failed to achieve a tree, 

 and that the rich vegetation of the coal measures had been exclu- 

 sively composed of magnificent immaturities of the vegetable king- 

 dom, — of gigantic ferns and club-mosses, that attained to the size of 

 forest trees, and of thickets of the swamp-loving horse-tail family of 

 plants, that well-nigh rivalled in height those forests of masts which 

 darken the rivers of our great commercial cities. Such was the view 

 promulgated by M. Adolphe Brongniai't ; and it may be well to 

 remark that, so far as the evidence on which it was based was posi- 

 tive, the view was sound. It is a fact, that inferior orders of plants 

 were developed in those ages in a style which in their present state 

 of degradation they never exemplify : they took their place, not, 

 as now, among the pigmies and abortions of creation, but among its 

 tallest and goodliest productions. It is, however, not a fact that they 

 were the highest vegetable forms of their time. True exogenous 

 trees also existed in great numbers and of vast size. In various lo- 

 calities in the coal-fields of both England and Scotland, — such as 

 Lennel Braes and Allan Bank in Berwickshire, High-Heworth, Fel- 

 lon, Gateshead, and Wideopen near Newcastle-upon-Tyne, and in 

 quarries to the west of the city of Durham, — the most abundant fos- 

 sils of the system are its true woods. In the quarry of Craigleith, 

 near Edinburgh, three huge trunks have been laid open during the 

 last twenty years, within the space of about a hundred and fifty yards, 

 and two equally massy trunks, within half that space, in the neigh- 

 bouring quarry of Granton, — all low in the coal measures. They lie 

 diagonally athwart the strata, — at an angle of about thirty, — with the 

 nether and weightier portions of their boles below, like snags in the 

 Mississippi ; and we infer, from their general direction, that the stream 

 to which they reclined must have flowed from nearly north-east to 

 south-west. The current was probably that of a noble river, which 

 reflected on its broad bosom the shadow of many a stately tree. 

 With the exception of one of the Granton specimens, which still re- 

 tains its strong-kneed roots, they are all mere portions of trees, rounded 

 at both ends, as if by attrition or decay ; and yet one of these portions 



