CONTRIBUTIONS TO PALEONTOLOGY, 108 



Feet. 



4. Reddish conglomerate, with slaty paste and rounded pebbles; trappoan 



or tufaceous rock; red, purplish and green sandstones and shales. 

 Thickness variable 1000 



5. Black papyraceous shale, with layers of cone-in-cone concretions 400 



6. Hard, generally coarse and miciceous grey shales and flags of various 



shades of color, and with some reddish shale and tufaceous or trap- 

 pean matter at the bottom. Lixgul^, Burrows, and Tra'ls of ani- 

 mals ^000 feet or more. 



7. White and grey crystalline limestone, with bands of shale and beds of 



graphite GOO feet or more. 



8. Gneissose and other metamorphic beds, with bands of quartz-rock and 



slate. Thickness unknown. 



The Devonian age of the upper members of this great series of beds I 

 regard as established by their fossils,* taken in connexion with the un- 

 conformable superposition of the Lower Carboniferous conglomerate. The 

 age of the lower members is less certain : they may either represent the 

 Middle and Lower Devonian, or may be in part of Silurian age. Their only 

 determinable fossil, the Lingula of the St. John shales, affords no decisive 

 solution of this question, and the evidence of mineral character is not to 

 be relied on in the case of beds so remote from those regions in which the 

 Devonian rocks of America have been most minutely studied. 



In mineral character, Nos. 1 & 2 of the above sectional list might very 

 well represent the Old Red Sandstone, or Catskill group of the New- York 

 geologists. Nos. 3 & 4 might be regarded as the analogues of the Chemung 

 and Portage groups. No. 5 would represent the G-enesee slate ; No. 6, the 

 remainder of the Hamilton group ; No. 7, the Corniferous limestone ; and 

 No. 8 might be regarded as a metamorphosed equivalent of the Oriskany 

 and Schoharie sandstones. The entire want of the rich marine fauna of 

 these formations is, however, a serious objection to this parallelism. If, on 

 the other hand, we employ as our scale of comparison the development of 

 the Devonian system of Gaspe, Nos. 1 & 2 will correspond with the upper 

 member of the Gaspe series, and No. 3 with the rich plant-bearing beds of 

 the middle of that series ; but no mineral equivalent of the St. John shales 

 and limestones occurs at Gaspe, unless we seek for it in the Upper Silurian. 



The rocks of the St. John group extend along the coast as far as. the 

 frontier of Maine ; and there can scarcely be any doubt that the plant- 

 bearing beds at Perry represent some portion of the St. John series, most 

 probably Nos. 2 & 3 of our sectional list. At Perry the plant-beds rest on 

 a trappean bed, which may be the equivalent of our No. 4, a member of 

 the series much more constant in its occurrence than would be anticipated 

 from its composition. According to Prof. Hitchcock, this last bed rests 



* The scanty animal remains of the plant-beds No. 3 accord very well with the evi- 

 dence of the fosil plants : they are a small Trilobite, apparently a Phillipsia; three 

 other Crustaceans, one of which is probably a Stylonurus, another a Eukyptehus, 

 and the third a Decapod not apparently referable to any described genus. These Cru- 

 staceans are now in the hands of Mr. Salter ( See his paper on these fossils, read 

 before the Society, May 21, 1862). There is also a shell, apparently a Loxonema, and 

 a Spirorbis. 



