Geological Society. 



389 



one point near the base of the largest tree, and though indistinct, his 

 practised eye recognised them to be those of a Sigillaria. He de- 

 tected also in some parts, on the ribs of the same tree, the fine wavy 

 lines so often visible on decorticated specimens of that family. In 

 describing the second tree, he alludes to a deep wedge-shaped rift 

 on the south-east side, which had been coated with coal, and is 

 strongly marked with wavy lines, like those on the surface of the al- 

 burnum of a gnarled oak. On the fifth tree, he discovered a longi- 

 tudinal concavity on the north side, and he states that it resembles 

 the impression which would be left in a dicotyledonous tree, by the 

 pressure of a parasitic plant. The characters of the roots are also 

 detailed at considerable length, particularly their mode of bifurcation, 

 and position with respect to the horizon. 



From a careful consideration of the phenomena presented by the 

 fossils, Mr. Bowman is convinced that they stand where they origin- 

 ally flourished ; that they were not succulent, but dicotyledonous, 

 hard- wooded forest trees ; and that their gigantic roots were mani- 

 festly adapted for taking firm hold of the soil, and in conjunction 

 with the swollen base of the trunks to support a solid tree of large 

 dimensions with a spreading top. 



Towards the close of 1838, in forming the railway tunnel at Clay- 

 cross, five miles south of Chesterfield, a number of fossil trees were 

 found, standing at right angles to the plane of the strata. The tunnel 

 passes through the middle portion of the Derbyshire coal measures, 

 which there dip about 8° to a little north of east. The bases of the 

 trees rested upon a seam of coal fifteen inches thick. The exterior 

 of the stems consisted of a thin film of bright coal, furrowed and 

 marked like the Sigillaria reniformis ; and the interior consisted of a 

 fine-grained sandstone. Mr. Conway, who supplied Mr. Bowman 

 with an account of the discovery, infers, from the information which 

 he obtained, that there must have been at least forty trees found, 

 and judging by the area excavated, he is of opinion that they could 

 not have stood more than three or four feet apart. There were no 

 traces of roots, the stems disappearing at the point of contact with 

 the coal. Several specimens of Stigrnaria Jicoides were also noticed 

 by Mr. Conway, lying horizontally and about three feet in length. 



With reference to fossil trees in general, and especially to those 

 near Manchester, Mr. Bowman proceeds to show still further ; 1st, 

 that they were solid, hard- wooded, timber trees, in opposition to the 

 common opinion that they were soft or hollow ; 2nd, that they ori- 

 ginally grew and died where they have been found, and consequently 

 were not drifted from distant lands ; and, 3rd, that they became hol- 

 low, by the decay of their wood, from natural causes, similar to those 

 still in operation in tropical climates, and were afterwards filled with 

 inorganic matter, precipitated from water. 



1 . In stating his reasons for believing that the coal measures' casts 

 were solid timber trees, Mr. Bowman alludes to the rifting of the 

 bark of modern forest trees, in consequence of the expansion caused 

 by the annual addition of a layer of wood between the bark and the 

 alburnum ; and to the thickening or swelling of the base of the trunk 



