70- SIXTEENTH REPORT ON THE CABINET OF NAT. HISTORY. 



collection from the Niagara group of New- York, or of Iowa, 

 Wisconsin or Northern Illinois.* Among some collections made in 

 1860 & 61 from Waldron, Indiana, a single species, the Astylo- 

 spongia pnBinorsa, occurs in considerable numbers ; but the speci- 

 mens are much smaller than most of those in my collection from 

 Tennessee. In the same association with this species are numerous 

 known species of the age of the Niagara group, including one 

 Crinoid, several Brachiopoda, and Crustacea. 



I have had in my collection, for many years, a species of 

 AsTYLospoNGiA from the Lower Helderberg group. It occurs chiefly 

 in the shaly calcareous layers, but is sometimes found in the lime- 

 stone. The form is globose or subglobose ; some of the specimens 

 being a quarter of an inch in diameter, and others having a dia- 

 meter of an inch and a half, and perhaps more. The surface is 

 without ornamfent, being neither lobed, striate nor sulcate ; though 

 from the point which appears to be the base, there are, in well- 

 preserved specimens, sometimes a few indistinct radiating lines. 



These bodies are frequently encased in a shaly coating ; and 

 the structure being obscure, they have doubtless often been ne- 

 glected, under the impression that they are small corals with a 

 shaly coating obscuring the cells, or that they are spherical con- 

 cretions, which they much resemble. In the weathered and par- 

 tially decomposed specimens the exteriar structure is well dis- 

 played, and a transverse section exhibits the characteristics of 

 other species of the genus. 



This species may be designated the Astylospongia inornata, from 

 the absence of external ornament or marking, and which will 

 distinguish it from any of those cited above. 



This species is of common occurrence at the Helderberg mountains and 

 at Schoharie. t 



* It is possible that some of the small spheroidal bodies in the Niagara shale, which 

 are usually decomposed by the presence of sulphuret of iron, may belong to this group 

 of fossils. 



t To those who have facilities of studying with the microscope, these spheroidal 

 concretion -like bodies offer inducements for investigation. The more calcareous ones 

 display structure without preparation; while the silico-calcareous ones require to be 

 macerated in acid, after cutting or grinding the surface. It is quite probable that a 

 more critical examination may disclose the occurrence of similar bodies in some portion 

 of the Niagara group or Coralline limestone. 



