36 



PALAEONTOLOGY OF NEW YORK. 



S. raricostus, Conrad, 

 (?) S. Knappianus, Nettelroth, 

 (?) S. disparilis, Hall, 



S. zic-zac. Hall = S. consobrinus, 

 D'Orbigny, 



S. mesacostalis, Hall, 



2. Aseptati : 



a. Mucronatus-type : 



S. segmentus. Hall, 



S. arctisegnientus, Hall, 



S. mucronatus, Conrad, 



(S. bidorsalis, Winchell, 



S. sculptilis, Hall, 



S. Hobbsi, Nettelroth, 



S. Byrnesi, Nettelroth, 



S. varicosus, Hall, 



S. subattenuatus, Hall, 



S. bimesialis, Hall, 



S. desideratus, Walcott, 

 h. Submucronatus-tjpe : 



S. Engelmanni, Meek and Worthen= 

 S. Worthenanus, Schuchert, 



S. submucronatus, Hall, 



S. CumberlanditB, Hall, 



S. macrus, Hall, 



S. Davisi, Nettelroth, 

 (?) S. gregarius, Clapp, 



Upper Helderberg group. 

 Upper Helderberg group. 

 Upper Helderberg group. 



Hamilton group. 

 Chemung group. 



Upper Helderberg group. 



Upper Helderberg group. 



Hamilton group. 



Hamilton group. 



Hamilton group. 



Hamilton group. 



Hamilton group. 



Hamilton group. 



Hamilton and Chemung groups. 



Hamilton and Chemung groups. 



Lower Carboniferous. 



Oriskany sandstone. 

 Oriskany sandstone. 

 Oriskany sandstone. 

 Corniferous limestone. 

 Corniferous limestone. 

 Corniferous limestone. 



III. FlMBRIATi: 



1. Unicispinei =Delthyris, Dalman, 1828 

 a. Crispus-type : 



S. crispus, Hisinger, 



S. crispus, var. simplex. Hall, 



S. Vanuxemi, Hall, 



S. Saffordi, Hall, 



S. cyclopterus, Hall, 



Niagara group. 

 Niagara group. 

 Lower Helderberg group. 

 Lower Helderberg group. 

 Lower Helderberg group. 



