NO. 9 NEW YORK POTSDAM-HOYT FAUNA 257 



the Cambrian and the superjacent system of strata, or as belonging to 

 the higher systems/ With the evidence now known to me from New 

 York and the Appalachian region to the southwest I am inclined 

 tentatively to refer the fauna as found in New York State to the 

 upper limit of the Cambrian. (See pages 255 and 256 for further 

 discussion of this question.) 



My present view is that the use of the name Saratoga should be 

 restricted to the Cretaceous formation, another name adopted for the 

 group of formations included in the Upper Cambrian, and another 

 name for the Potsdam-Hoyt fauna if that fauna is considered as 

 distinct from the Upper Cambrian fauna. 



When looking up a name for the Upper Cambrian formations in 

 1903, I thought of St. Croixan, but as the name St. Croix had become 

 fixed in geological literature for the Cambrian sandstone of the 

 Upper Mississippi Valley' I did not use it. In 191 1' Dr. E. O. 

 Ulrich proposed to use the name St. Croixan for the sea in which the 

 St. Croix sandstones were deposited, and in his table of correlations 

 of formations (pi. 27) and on page 614 of the same work he uses the 

 term as a collective name for his Upper Cambrian formations. If 

 we drop the term " St. Croix " as a formation name for the sand- 

 stones of Wisconsin and Minnesota containing the Upper Cambrian 

 fauna, then the term St. Croixan may be used for the assemblage of 

 formations characterized by the Upper Cambrian fauna. 



DESCRIPTIONS OF GENERA AND SPECIES 



Genus CRYPTOZOON Hall 



Cryptozoon Hall, 1884, Thirty-sixth Ann. Rept. New York State Mus. Nat. 

 Hist., desc. of pi. 6. (Genus described and discussed as below.) 



The original description is as follows : 



In the town of Greenfield, Saratoga County, there occurs a bed of limestone 

 which presents a very remarkable appearance, the surface being nearly covered 

 by closely arranged circular or subcircular discs which are made up of 

 concentric laminae, closely resembling in general aspect the structure of 

 Stromatopora. It very often happens 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 



* See Ulrich, Bull. Geol. Soc. America, Vol. 22, No. 3, 191 r, pi. 27, and p. 612. 



* See N. H. Winchell, 1873, Ann. Rept. Board of Regents, University of Min- 

 nesota. First Ann. Rept. Geol. and Nat. Hist. Surv. for 1872, pp. 68-80. 



* Ulrich, Bull. Geol. Soc. America, Vol. 22, No. 3, 1911, p. 613. 



