NO. 9 NEW YORK POTSDAM-HOYT FAUNA 253 



The " Saratogan " fauna of New York was correlated with the 

 Dicellocephalus fauna of the Upper Mississippi Valley in 1879/ and 

 in 1891 the list of fossils was corrected by the recognition of the 

 genus Dicellocephalus^ 



In proposing the name *' Saratogian " a list of the fauna at the 

 Hoyt quarry was given as follows : ^ ' 



" Cryptozoa proliferum. Billingsia saratogensis. 



Obolus (Lingulepis) acuminatiis. Matthevia variabilis. 



Platyceras minutissimum. Dikeloccphalus hartti. 



Platyceras hoyti. Dikeloccphalus speciosus. 



Metoptoma cornutifornie. Ptychoparia calcifera. 



Metoptoma simplex. {A.) saratogensis." 



In a small drift block of sandstone I found on the road from 

 Trenton to Trenton Falls, Oneida County, New York, in 1867, there 

 is an unusual, apparent association of Upper Cambrian (Hoyt lime- 

 stone) and Ordovician (Aylmer sandstone, Chazy) fossils. The 

 Hoyt limestone species are Ptychaspis speciosus and Agraulos cf. 

 saratogensis. The Aylmer sandstone species are Leperditia armata, 

 L. sp. ?, and Bathyurus cf. angelina Billings. 



When, as a boy, I found the rounded block of sandstone referred 

 to I broke out all the fossils possible, as at the time I was well 

 acquainted with the Trenton limestone fauna, and the fossils in the 

 block were strangers to me. with the exception of Leperditia armata. 

 The following winter I endeavored to locate the stratigraphic posi- 

 tion of the trilobites, but could not, further than that they were 

 evidently of pre-Trenton age. This study aroused an interest in the 

 American early Paleozoic fossils that gradually led me to take up the 

 Cambrian rocks and faunas as my special field of research. 



The block of sandstone was about 3 inches in thickness by 12 in 

 diameter. The impact of the wheel of the wagon in which I was rid- 

 ing split the block open and exposed several cranidia of the trilobite 

 now known as Ptychaspis speciosus. Neither this nor Agraulos cf. 

 saratogensis occurred in direct association with the Chazy Leperditia 

 and Bathyurus. This now leads me to adopt a suggestion of Dr. 

 E. O. Ulrich that the block of sandstone was part of a bed formed by 

 the overlap of the Aylmer sandstone of the Chazy on a layer of Pots- 

 dam sandstone. This would make the line of demarcation between 



Walcott. Thirty-second Ann. Rept. New York State Museum, 1879, p. 131. 

 ' Bull. U. S. Geol. Survey, No. 81, 1891, p. 346. 

 'Journ. Geol., Chicago, Vol. 11, No. 3, 1903, p. 318. 



