252 NEW YORK STATE MUSEUM 



in the shale than in the Hmestone, e. g. it is questionably present in 

 the dense bine limestone of K7, while 21 inches higher in K8, a 

 dark gray shale, it is exceedingly abundant. 



S. macrus Hall 



Quite abundant in the lower beds of the Onondaga. No perfect 

 valves were found. One very smiall specimen with a length of 

 about 7mm and a width of 20mm has a cardinal area 2mm high and 

 moderately concave ; it has apparently six plications on each side of 

 the sinus. Another partial pedicle valve, lomm by 24mm, has nine 

 plications on each side of the sinus, crossed by many lamellose, con- 

 centric striae. It looks very much like S. mucronatus but 

 has a very much higher cardinal area. The largest specimen 

 observed has an apparent width of 40mm. 



Delthyris perlamellosa (Hall) 



Abundant in the Coeymans and the whole of the New Scotland. 

 It is very rarely found in the Becraft. This usually occurs in the 

 same lithologic beds in the New Scotland as S. macropleura but 

 unlike it, an apparently greater vitality enabled it to thrive in pure 

 waters also. 



Eeticularia fimbriata (Conrad) 



One shell from the lower Onondaga measures 22mm by 35mm by 

 i8nim. The sinus is broad and of medium depth (not quite 2mm). 

 The fold is quite high toward the front (3.5mm), but fades out be- 

 fore reaching the umbo. There are five low, rounded plications on 

 each side of the fold and six on each side of the sinus. The con- 

 centric lamellae are quite prominent and imbricating toward the 

 front of the shell. The specimen is much exfoliated but there appears 

 to be an average of two elongate nodes to imm of width. Several 

 specimens of fragmentary Spirifers from the upper portion of the 

 exposed Onondaga may also belong to this species. 



R. modesta (Hall) 



This little spirifer is present in our collection only from the Coey- 

 mans, Lower New Scotland and Upper Oriskany. 



