90 



On the Silurian System. 



11. Gypseous shales, 

 10. Lockport limestone, 



9. Rochester shale, 



8. IstPentamerus lime- 

 stone, 

 7. Green slate and iron 

 ore, 

 Top stratum. 

 6. Niagara sandstone, 

 5. Olive sandstone and 

 shale of Salmon river, 

 f Black slate, 



'^ Trenton limestone, 



Eurypterus remipes. "^ g 



Catenipora, (new.) | q" 



' Asaphus limiilurus, Platynotus, Trimerus delphino- )■ g- 

 cephalus, Orthis elegantula, Strophomena trans- j xn 



' versalis, Caryocrinus. J pj 



3. Sparry limestone, 

 2. Mohawk limestone, 

 Calciferous and Pots- 

 dam sandstone, 

 Hudson slates, 



^ Pentamerus oblongus. 



C Agnostus latus, Strophomena corrugata, Tentacu- 



\ lites parvus. 



C Dictuolites Beckii. 



\ Fucoides Harlani, Lingula cornea. 



> Pterinea carinata, Cyrtolites ornatus. 



Triarthrus Beckii, Graptolites or Fucoides dentatus. 

 C Orthis testudinaria, O. callactis, Strophomena seri- 

 ^ cea, S. deltoidea, Calymene Blumenbachii, C mi- 

 ( cropleura, Cryptolithus, Isotelus. 



Fucoides demissus. 



Orthostoma communis. 



O 



Lingula cuneata. 

 Graptolites, (Fucoides serra.) 



Species com/moji to the Silurian rocks of Wales and the United 



States. 



LUDLOW KOCKS. 



Shells. 

 Cyrtoceras (Phragmoceras) giganteum, 

 Orthoceras pyriforme, 

 Bellerophron expansus, 

 Orthis orbicularis. 



Corals. 

 Cyathophyllum ceratites, 

 helianthoides, 

 turbinatum, 

 dianthus, 

 Catenipora escharoides, 

 Fav osites fibrosa, 



spongites, 

 gothlandica. 



WENLOCK LIMESTONE. 



Shells. 

 Tentaculites annulatus, 

 Strophomena euglypha, 

 rugosa, 

 (Lepta3nadepressa, Sow.) 

 Pentamerus galeatus, 



(Atrypa galeata, Dalm.) 

 Atrypa prisca, 



(affinis. Sow.) 



aspera, 



lacunosa, 



tenuistriata, 



bidentata. 



Trilohites. 

 Calymene bufo, 



(C. macrophthalma,) 

 Asaphus limulurus.* 



* This appears to be the same with Murchison's A. longicaudatus, and is very 

 distinct from the true caudatus, which has not I believe been found in New York; 

 I have received from Dr. William Fleming, of Manchester, fine specimens of the 

 latter in limestone, from Dudley. The former is common in the Rochester shales, 

 and I have not seen it from any other formation. I also received from Dr. Fleming 

 a specimen of A. limulurus, from Dudley. 



