r 



PENTAMERUS LIMESTONE. 119 



At the falls of Chittenango creek below Cazenovia, just under the Onondaga and Oriskany 

 sandstone, a layer or two of impure limestone is seen, containing rounded grains of white 

 transparent quartz, with some imperfect shells which resemble the Galeated pentamerus ; 

 being all that was seen, which appeared to belong to this rock in Madison county, to the 

 west of the falls of Oneida creek. 



There are several other fossils associated with the pentamerus, and it may be well to note 

 two or three of them. It contains two atrypae, of a kind which first appears in this district 

 and State in this rock, and there are three in all. Beyond this State there are others, one of 

 which exists in a lower position in Ohio and Indiana, being the A. capax of Conrad ; the third 

 is confined to the Tully limestone, being the A. cuboides. The two which are found in the 

 pentamerus hmestone, closely resemble the Terebratula wilsoni as figured by the EngUsh 

 geologists. The one given by Mr. Lyell in the Boston edition of his Geology, will be the 

 Wilson atrypa ; and the one in Mr. Murchison's work, the Inflated atrypa (A. inflata). The 

 ribs or ridges in this division of atrypae are divided into three portions ; those of the middle 

 one in each of the New-York species, are seven in number, which would appear also to be 

 the number in those of Europe. 



The Atrypa lacunosa (No. 3 of the wood-cut), so named by Mr. Conrad from identity with 

 the one of Europe, is readily distinguished from the others by its high and sharp ridges and 

 deep furrows, all which pass under the beak with graceful curves. 



The pentamerus limestone is burnt for hme in several places along its range. A number 

 of kilns may be seen by the road-side in the town of Springfield, &c. 



The thickness of this rock was not ascertained by measurement. Its maximum is in 

 Otsego county, where it can not be less than eighty feet. It diminishes towards the west, 

 being not much over ten feet at Oneida creek, and the hmit there is not so well defined as at 

 the east. 



The following list presents all the fossils belonging to this rock, which have been identified 

 and named by Mr. Conrad up to this time. 



Testacea or Shells. 



Pentamerus galeatus. Strophomena rectilateris. 



Atrypa lacunosa. — impressa. 



— semiplicata. — elongata. 



Euomphalus profundus. Avicula naviformis. 



Strophomena varistriata. — manticula. 



