species. New species similar to this one are known in the 

 lowest Ordovician (Beekmantown) formations of the United 

 States, and it is barely possible that, on account of the 

 similarity, your specimens are from the same horizon.' ' 



The genus (CryptozoonJ was established by Professor 

 James Hall, in 1884. 0-) Hall's description has been quoted, 

 in extenso, by Dr. Walcott.( 2 ) As the literature on the sub- 

 jects is limited and not very accessible, it may be found useful 

 to reproduce Hairs description here : — 



"In the town of Greenfield, Saratoga County, there occurs 

 a bed of limestone which presents a very remarkable appear- 

 ance, the surface being nearly covered by closely arranged 

 circular or sub-circular discs which are made up of concentric 

 laminae, closely resembling in general aspect the structure of 

 Stromatopora. It very often happensi that within these larger 

 discs there occur two or more smaller ones, each with its own 

 concentric structure and exterior limitation, and appearing 

 as if budding from the parent mass. A farther examination 

 shows that the entire form of these masses is hemispheric 

 or turbinate, with the broadest face exposed upon the upper 

 surface of the limestone layer ; that their growth has begun 

 from a point below, and, rapidly expanding upwards, has 

 often extended one or two feet in diameter, as now shown 

 upon the exposed surface of the limestone bed. At a single 

 exposure on the farm of Mr. Hoyt, the surface of the limestone 

 is covered by these bodies for many rods in extent. The entire 

 area of the cellar beneath the house of Mr. Hoyt is upon this 

 bed of limestone closely covered by these hemispheric masses 

 with concentric structure. For a distance of one or two miles 

 to the southward the outcrop of the limestone can be traced, 

 and everywhere presenting the same characters in the presence 

 of these masses. Large numbers of specimens of various sizes 

 have been weathered out and lie scattered over the surface. 

 This fossil has also been found at Little Falls, Herkimer 

 County, New York. 



"These bodies have long been known under the name of 

 Stromatopora, from their general resemblance in form and 

 structure to that fossil ; but their position in reference to 

 the bedding of the rock is uniformly the reverse of that of 

 Stromatopora? , which occur in the higher limestones, growing 

 from a broad base which is covered by an epitheca, while 

 these bodies under consideration grow upward and expand 



(1) Thirty-sixth Ann. Rept. New York State Mus. Nat. Hist., 

 description of pi. vi. 



(2) Smithsonian Miscell. Coll., vol. lvii., No. 9. Idem, pi. 

 xxxvii., photo, of C. proliferum, by Dr. Walcott. 



