1854.] 65 



but beautiful pellicle, covering the impressions of the plants. These trunks and 

 Jimbs are of all sizes, from an inch to nearly three feet in circumference, strewed 

 about, and piled upon each other in the most irregular manner, and so numerous 

 that scarcely a fragment of rock was thrown out which did not contain either a 

 vegetable impression or a silicified stem. 



Although in the shale above, vast piles of detached fern leaves were found, be- 

 longing principally to the genus Neuropteris t accompanied with numerous im- 

 pressions of Calamites, yet no species of fern was discovered in the sandstone, 

 with the exception of two specimens, both of which belonged to distinct genera. 

 The one was a Pecopteris, and the other was the Cyclopteris trichomanoides , 



Among the numerous arborescent fossil plants which were found in this sand- 

 stone, was an entire tree of immense magnitude, lying prostrate, about four feet 

 above the Pittsburgh seam of coal, and about thirty feet beneath the surface. 

 The part which was removed measured twenty six feet in length, and two feet 

 ten inches in circumference at the base. From the size of the two main branches 

 which enter the rock on the opposite side, I infer that this tree may have been 

 from forty to sixty feet in height. At the base, it was much flattened by the 

 pressure of the superincumbent weight, but strange as it may seem, the branches 

 still retained nearly their original cylindrical form. It was entirely enveloped in 

 a coating of pure bituminous coal, varying from a quarter of an inch to one inch 

 in thickness. Its interior was filled with sand, mixed with sulphuret and car- 

 bonate of iron, which much increased its weight, but there were no indications 

 of vegetable structure. The thin vegetable band, which alone remained con- 

 verted into pure bituminous coal, may have surrounded an axis of more perishable 

 material, which, when the tree was removed from its original position by the 

 storms or the Waves, rapidly decayed. Its hollow interior would necessarily be 

 filled with sand, broken shale or other sediment which was brought by large 

 rivers into that turbulent sea, the bed of which was gradually subsiding. This 

 view is corroborated by the fact, that the rock in which this plant is found 

 imbedded, and which constituted its matrix, presents an entirely different appear- 

 ance in color, and in some degree in lithological character, from that which fills 

 the interior of the fossil tree. Although there were numerous, but irregular 

 longitudinal flutings, both along the main irunk and its branches, yet I could 

 discover no indications of those beautiful scars, so characteristic of arborescent 

 ferns, and of the genus Sigillaria, which indicate the spots where the petioles 

 of the leaves articulated with the stem ; and hence I infer that this tree should 

 not be referred to either of those families of plants. 



The question naturally arises, to which of the three great divisions of the 

 vegetable kingdom do these fossil trees belong. Do they belong to arborescent 

 ferns, gigantic palms or lofty pines ? Are they of exogenous or endogenous 

 growth ? 



It has been said by fossil botanists, that true exogena? and endogenae have been 

 found in the carboniferous rocks of Europe. I have, therefore, been much inter- 

 ested in discovering some clear indications of these highest forms of vegetable 

 structure, in the coal measures in this country ; but 1 have thus far failed, unless 

 the specimens to which I have already alluded, should on further examination, 

 prove exceptions. 



I am aware that M. Brongniart has placed the Sigillariae among the exogenae, 

 but with all due deference to his high authority, I must say that I have been 

 unable to find in that family of fossil plants any evidence of pith, bark, con- 

 centric rings, medullary rays, or other indications of so high a structure. 



Since writing the above,! have made another examination of the specimens of 

 fossil trees, and believe that I was at first mistaken in regard to some of them 

 being branches. The rock in which they were found had been blasted, and 

 consequently the fossil trees were much broken. The largest entire piece which 

 I saw was not more than four or five feet in length. These facts may have 

 some bearing upon their position in the vegetable scale. 



