GEOLOGY OF THE FOURTH DISTRICT. 



ORGANIC REMAINS OF THE NIAGARA GROUP. 



No. 12. — No. 35, page 104 of Rrport. 



Fig. 1. Strophomena subplana, C. (Jour. Acad. Nat. Sci., vol 8, page 258.) Lockport. 



Fig. 2. Strophomena depressa, Productus depressus, M. C. t. 459. (Leptama depressa, Dal- 

 man. Swedish Transactions, p. 106, t. I, f. 2 ; Hisinger, Petrefacla Succica, 

 p. 69, t. 20, f. 3. Mukchison, Silurian Researches, p. 623, pi. 12, f. 2.) An 

 abundant fossil in the shale of the Niagara group. Lockport. 



Fig. 3. Strophomena. striata, H. Common at Rochester and Lockport. 



Fig. 4. Strophomena transversalis. (Leptccna transversalis, Dalm. 1. c. p. 109, t. 1, f . 4 ; 

 His. Pet. Suec. p. 69, t. 20, f. 5. Silurian Researches, p. 629, pi. 13, f. 2.) 



No. 13.— No. 3G, page 105 of Report. 

 Fig. 1. Delthjris Niagarensis, Conrad (Jour. Acad. Nat. Sci. vol. 8, p. 261). Lockport. 

 Fig. 2 and 2 b. Delthjris radiatus. (Spirifer radiatus, M. C. t. 493. Silurian Researches, p. 



624, pi. 13, f. 6.) Lockport. 

 Fig. 3 and 3 b. Dellhyris staminca, H. (References, Spirifer crispus ? Silurian Researches, 



p. 624, pi. 13, f. 8. Dellhyris crispa, Dalm. 1. c. p. 122, t. 3, f. 6; His. Pet. 



Suec. p. 73, t. 21, f. 5). lockport. 

 Fig. 4 and 4 a. Delthyris decemplicata, H. Lockport; and Delthyris sinuatus. (Tcrcbratula 



sinuata, Sowerhy in Linn. Trans. Vol. 12, p. 516, t. 28, f. 5 and 6. Delthyris 



cardiospermiformis, His. Anteckn. Vol. 4, t. 7, f. 6. Dalm. sur les Tcrebratules, 



p. 124, t. 3, f 7. His. Pet. Suec. p. 74, t. 21, f. 9. Spirifer cardiospermiformis, 



Von Buch sur les Spirifers et Orthis, t. 1, f. 7. Spirifer sinuatus, Silurian 



Researches, p. 630, pi. 13, f. 10 ) Wolcott. 

 Fig. 5. Orthis jlabellulum (a)? (Silurian Researches, pi. 21, f. 8. O. callactis ? Dalman.) 



Lockport. 

 Fig. 6. Orthis canalis, (Silurian Researches, p. 630, pi. 13, f. 12, a ; also pi. 20, f. 8. Orthis 



elegantula ? Dalman. Von Buch sur les Spirifers et Orthis, pi. ii, f. 3, 4 and 5 ) 



Sweden, Monroe county. 

 Fig. 7, a, b, c. Orthis hybrida, (Silurian Researches, pi. 13, f. 11.) Sweden, Monroe county. 



No. 14 — in part No. 37, page 108. 



Fig. 1. Atrypa imbricata. (Terebratula imbricata, Silurian System, p. 624.) 



Fig. 2. Atrypa. (Species undetermined ) Lockport. 



Fig. 3, 4 and 4 a. Atrypa cuneata. (Terebratula cuneata, Dalman. Hisinger. Silurian Re- 

 searches, p. 625, pi. 12, f. 13.) 



Fig. 5. Atrypa nitida, H. A very abundant species, but usually more or less distorted. 

 Lockport. 



Fig 6. Atrypa affinis, (Terebratula affinis. M. C. t. 324, f. 2. A. reticularis, Dalman, 

 Hisinger, &c.) 



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