Fossil Vegetables, 109 



thick. The bark is converted into coal. In the great coal field of 

 the north, fossil plants are generally found in a horizontal position or 

 parallel to the strata, but much broken and compressed, with their 

 parts far separated. But large and vigorous plants are sometimes 

 found which appear to have been strong enough to withstand the force 

 of torrents, if such existed, and to have remained in their natural posi- 

 tions. These vertical plants are generally Sigillarise. The Stigmariee 

 and the Equisetaceas do not appear to have been strong enough 

 to have resisted such revolutionary influences. Great numbers of 

 Gymnospermous Phanerogamic plants have been lately discover- 

 ed in the shales of the mountain limestone group, much broken, 

 and lying in a state of great confusion. Other discoveries of fos- 

 sil trees have been made in the same quarry, in which the above 

 named plants were found, particularly two immense Conifers, and 

 there appears strong reason to believe, that in a square mile of the 

 same deposit, many other ancient relics of early vegetation will be 

 brought to light, and thus induce the belief that these plants are as 

 abundant in these deposits, as in those higher up in the strata. Some- 

 times the composition of the fossil vegetables is similar to that of the 

 strata in which they lie, and sometimes it is either wholly or partially 

 different, and the variation must be accounted for from the operatiorr 

 of local causes. The composition of the Craigleith fossil, named 

 above, was carbonate of lime 62, carbonate of iron 33, carbon 5, and 

 the specific gravity was 2.87. The composition of the Craigleith 

 tree discovered in 1826 was carbonate of lime 60, oxide of iron IS, 

 alumine 10, carbon 9, loss 3, and several specimens from other places 

 had a similar composition. 



A fossil plant from the quarry of Neworth near Newcastle, between 

 the encrinal or mountain limestone and the new red sandstone depos- 

 its, was, silica 95, peroxide of iron and alumine 5. 



The discoveries of Mr. Witham induce us to believe that plants 

 of the gymnospermous phanerogamic class are much more abundant 

 in the early sedimentary deposits than continental writers have sup- 

 posed. 



We are led to the curious and unexpected conclusion that proper 

 trees, of true ligneous fibre and of great size, existed, even earlier than 

 the bituminous coal, and that the great coally deposits are probably 

 due, in part, to them, as well as to the vascular cryptogamic plants, 

 whose remains are so abundant in these strata. 



It is therefore possible that wood maybe found, even with the ear- 

 liest fragmentary rocks, probably with the grauwacke itself. 



