1870.] ^-i' [Wincliell. 



species Avicula longispina and acanthoptera, Hall, are also abundant, as 

 ■well as a Bhyndionella, wliicli differs from any known Waverly species. 



It seems, therefore, from these indications, that the line separating the 

 Chemung and Waverly, passes between these two horizons ; and that we 

 have here positive paleontological and stratigrai)hical evidence of the su- 

 perposition of the Waverly- above the Chemung, as I have heretofore ar- 

 gued. "^ 



The fossils from Tennessee iden tilled with species of the age of the 

 Marshall (or Waverly) Group, will undoubtedly be regarded as possessing 

 considerable interest, as this is the first paleontological determination of 

 the extension of this group into that State. They are mostly embraced 

 in a tliin deposit of dark,_^ silicious, bituminous shales, emitting an agree- 

 able aromatic odor,''^ and resembling in physical characters, the shales of 

 the Kinderhook Group, of Illinois. This resemblance suggests the belief 

 that the Hickman shales of Tennessee are a prolongation of the Kinder- 

 hook shales ; and that they will yet be traced along both sides of the Coal 

 Measures, from Indiana and Illinois across the western extremity of Ken- 

 tucky. 12° 



Zaphrektis Ida? Win. (Proc. A. Nat. Sci., Phil., July, 18G5). From 

 Hickman county, Tenn., and Sciotoville, Ohio, (See Andrews' section). 

 The Tennessee specimens are without epitheca, and lack the profound 

 wrinkles of growth belonging to the types of this species, from Rockford, 

 Ind. They also enlarge upward somewhat more rapidly. The Ohio spe- 

 cimen is extremely similar to these. 



Tkematopora ? VESICULOSA, AViu. (Proc. A. Nat. Sci., Phil., Jan., 

 1863, p. 3). Several good specimens from Sciotoville, Ohio. 



"s See especially Proc. Amcr. Phil. Soc, ]S'o. SI, p. 57, and Proc. Acad. Nat. Sci., Phil., July, lS(i.5, 

 p. 11(1. 



113 See further notices of these rocks. Geology of Tenn., chap. XT, sec. I. 



1-° Descriptions of these fossils are embraced in the late Keport on Tennessee, in a paper etn- 

 bodying notices of some fossils from the "Carboniferous Limestone," of that State. As Prof. Saf- 

 ford has questioned the correctness of my identification of Spiri/era Loc/nni, I embrace this oppor- 

 tunity to state that I have reinvestigated the question and remain of the same persuasion as be- 

 fore, though 1 admit there is room for dilferences of opinion. I have five specimens of .S. imlircj-, 

 (to which Prof Saftbrd refers the specimens in question) from the typical locality, at Burlington, 

 Iowa. The Tennessee specimens differ from these as follows : They are larger, heavier iind coarser 

 shells; the sinus is more deeply sunk, relatively broader, and more distinctly defined, and it is 

 greatly produced in front, while that of.?, imbrex is scarcely at all produced ; it embraces from 10 

 to 12 costas, while that of .y.-imiz-ev embraces only 6 or 8; the fold, instead of being obsolete, and 

 a mere undefined swell, is raised into a prominent, crest-like, acute ridge, especially toward the 

 front; the dorsal valve is flattened from the middle of the fold to the extremities; the area is not 

 flat, and is striated in both directions; the costa^ besides being smaller, ai'e less numerous, except 

 In very old specimens ; they are crossed only by fine concentric striae, and remote irregular grooves . 

 instead of coarse, regular, imbiicating striae raised into nodes on the crests of the costa?, as is the 

 case with the surface of S. imbrex, when well preserved. 



On the contrary, these specimens agree with .?. Locjnvi, especially in the following distinctive 

 characters; " Dorsal valve depressed toward the cardinal extremities, and broadly curving to the 

 base; mesial fold very prominent, extremely elevated and subangular in front, not defined at the 

 margins. Ventral valve very gibbous at the sides, marked by a broad, deep, undefined mesial sinus 

 which, in the middle,of the shell, occupies fully one-third of the width, sloping abruptly to the 

 cardinal extremities, and extremely produced and elevated in front, in a sub-triangular exten- 

 sion;" the area is concave, vertically and longitudinally striate. 



The correct identification of these Tennessee specimens is important, as having a bearing on the 

 question of the equivalencies of the " Silicious Group,"' of Saflfbrd. 



