44 Land Pleads in the Lower Silurian. — Lesquereux. 



consideration.'' In a postscript to this letter, Mr. O'Neall confirms the 

 statement in regard to th6 specimens in question. 



There can be, therefore, no doubt as to the locality where these 

 vegetable remains have been found, or the geological age of the strata. 

 The clays of the Lebanon beds are full of Trilol)ites, of the same species 

 that abound in the clay beds at the base of the Cincinnati Group — 

 Calymene senaria. The only question to be settled is the true character 

 of the plant which the specimens represent. 



As I have said above, there were two fragments of small stems or 

 branches, referable to the same kind of vegetable; one, more complete, 

 about two inches thick, cylindrical, the whole substance transformed 

 into soft, gray clay, the bark, or the outer surface only, distinctly 

 moulded into clay, as is generally the case in specimens of this kind, 

 and marked by rhomboidal, continuous, enlarged bolsters, surrounding 

 the stem in a spiral, bearing at the middle a small oval or rhomboidal 

 scar, less distinct, however, though well recognizable, and presenting 

 the characters of stems of Sigillaria Serlii Brgt. or S. Menardi Brgt. 

 The study of the specimens, as far as I was able to do it, left me unde- 

 cided only in regard to their positive reference to the one or the other 

 of tliese two species, on account of the somewhat obscure form of the 

 internal scars. Though the Cincinnati Gi-oup has remains of Fucoids 

 of large size, none has as yet been found there, to my knowledge, as 

 large as these stems. And the peculiar form of the bolsters, placed 

 in spiral around the stem, similar in form, equal in size, regularly con- 

 vex, preclude the supposition that the remains represent some new 

 kind of marine plants, or are attributable to a concretionary structure. 

 We have, therefore, to admit them as representative of land plants, 

 and thus to recognize the existence of traces of land vegetation in the 

 Lower Silurian, tlie lower part of the Cincinnati Group being the 

 equivalent of the Trenton Group of New York. 



[The occurrence of vegetable remains in clay beds abounding in 

 remains of Trilobites is not subject to objection. The Coal-measures 

 of the West have strata of shale, clay, limestone, even sandstone, 

 where animal and vegetable remains are found together in abundance. 

 I have foimd Trilobites in the shale overlaying coal beds at Summit 

 Portage, Pennsylvania, with Sigillaria, Stigmaria, etc., and species of 

 the same kind of animals, with plants too, in sandy clay beds of the 

 upper Coal-measures of Indiana.] 



This discovery is the more remarkable, since we have, as yet, no 

 records of vegetable remains from the Silurian of North America, 

 except fragments of stems and rhizomes of Psilophyton, observed by 

 Dawson in the Gaspe Group of Canada. On these Dr. Dawson remarks : 



