376 New York State Museum 



cosum and several species of Platycems (P. ventricosum, 

 P. gebhardi, P. retrorsum, P. spirale etc.) ; the trilobites 

 by Dahnanites (Odontochile) pleuroptyx, Dahnanites 

 nasutus, Lichas pustulosus, Phacops logani and Ccrato- 

 cephala tuberculata. Among other fossils found are the 

 cup coral Streptelasma (Enterolasma) strictum, the 

 sponge Hindia inornata, the pteropod Tentaculites elon- 

 gatus and the cephalopod Orthoccras rude. Cri.noids are 

 represented by the base Aspidocrinics callosus and Edrio- 

 crinus pocilliformis. 



The Becraft limestone (Darton '94) received its name 

 from the exposure in Becraft mountain, Columbia 

 county. Previously it was known as the "Scutella" or 

 "Encrinal" limestone, from the presence of numerous 

 crinoid bases or Scutellas, and also as the "Upper Pen- 

 tamerus" limestone because of the occurrence of the 

 brachiopod Sieberella (Pentamerus) pseudogaleata. The 

 rock is very coarse-grained and not infrequently has the 

 character of a shell rock or coquina. Though usually 

 somewhat darkened on weathering, the rock is light col- 

 ored with pinkish and light gray, sometimes yellowish 

 tints. It is a very pure limestone on the whole and mas- 

 sive, forming conspicuous ledges. Chert is unusual. The 

 lower part of the formation is thinner-bedded with seams 

 of silicious shale, sometimes of a greenish color, one 

 to several inches thick. These seams have an abund- 

 ance of silicified fossils among which Atrypa reticularis 

 is common. The transition from the New Scotland to 

 the Becraft is not sharp, since the lower Becraft has 

 partings of shale and in the upper New Scotland occur 

 limestone bands that are packed with crinoidal fragments. 

 The Becraft limestone thickens southward and in the 

 type section at Becraft mountain near Hudson, where it 



