llie Lifv-llisiorii of Sjnrifcr Iwrlx. 140 



S. crispus, His., of tlie Coralline limestone. 



S. crispus, vur. simplex. Hall, of the Niagara, in Indiana. 



S. Vanuxemi (Vannxem), Hall, of the Lower Helderberg 

 Tentaculite limestone, and S. cydopterus, S. perlainellosus, 

 S. octocostatus and ;S'. Diodestus, H., all of the LoAver Hekler- 

 berg. 



S. Sajfordi and <S'. teiiiiistriatas, of the same period. 



*S'. fribidi.s, H., and rare examhles of S. fi))ihriatux, Con., 

 from the Oriskany. 



The varions forms of fimbria f lis of the Corniferons and of the 

 Hamilton periods, which might have received several specific 

 names if they were not so well represented in individnals. 



S. suhumbona, H., of the npper Hamilton, as well as of the 

 calcareons hands at its base. 



iSpirifer kevis, H., of the Portage, and »S'. pyeniaturus, H., 

 in the Chemnng further sonth. 



In the Carboniferons, such forms as ^S'. pseudoUneatus, H., 

 — setigerus, — plena, — octoplicatus and — liirtus, carry on the type 

 in this country; while in Great Britain and Europe a like series 

 extends from the Wenlock beds of the Silurian through to the 

 Carboniferous, and perhaps beyond ; but the specimens are not 

 at my hand for a full comparison and tracing of the later his- 

 tory. 



In the Wenlock and following Silurian beds, are the tli;'ee 

 xauQimi GoW^A Spirifer elevatus, Dalman, 8. crispus. His., and 

 — sidcatus. His. *S'. graiwsus, Vern., of Keyserling, in Russia 

 may belong to the gron]). 



In the DevoniaTi, are S. cur rat us, Schl., of the Ilfracombe 

 beds and elsewhere; Spiriferina cristata, Schl., and Sna. in- 

 sculpta, Phil., as defined by Davidson, are prob ibly in the line, 

 and Schnur's acuUatus, and the 8. cnrvatus, of the Eifel, are 

 also representatives. 



In the Carboniferons, the various modifications of Spirifer 

 glaber, Martin, and S. snlcatus, His., carry on the character of 

 the main types. 



spirifer lineatus. with which Hall compares several of the 

 Devonian forms in the United States, may be connected with 

 this line ; hut from the limited study I have been able to give it, 

 I am inclined to refer it to another series of forms, beginning 

 perhaps in S. radiatus of the Niagara. 



