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 atrypas, 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 limestone, closely resemble the Terebratula wilsoni as figured by the English 
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 atrypas 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 lime 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 limit 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. 
Atrypa lacunosa. 
— semiplicata. 
Euomphalus profundus. 
Strophomena varistriata. 
Strophomena rectilateris. 
— impressa. 
elongata. 
Avicula naviformis. 
— manticula. 
