RAYMOND: CORREL.\TION OF THE ORDOVICIAN STRATA. 261 



Ulrich has said of this fauna : " East of Minnesota we find it well 

 developed, though perhaps occupying only a few inches of limestone, 

 at the base of the Trenton in Northern Michigan, Ontario, Quebec, 

 New York and Northern New Jersey. In the Mohawk Valley in 

 New York, the bed containing this fauna is very thin and only locally 

 present." (119, p. 369.) 



The Fusispira fauna in Minnesota is characterized especially by 

 large gastropods, including Fusispira nohilis, F. inflata, F. ventricosa, 

 F. suhfusifonnis, F. vittata, and Hormoioma trentonensis and with them 

 are associated Cydospira bisukata, Rafincsqiuna dcUoidea, Sfropho- 

 mena trilobata and other fossils, though the brachiopods mentioned 

 seem to be found principally just below the real Fusispira zone. In 

 Ontario one finds exactly the same association, at Ottawa, at Picton, 

 Wellington and other places in southern Ontario and at CoUingwood 

 on Lake Huron. As I have already pointed out above, this fauna is 

 found in northern New York also at the top of the Trenton, and in 

 sections where one can see the whole Trenton from base to top, as for 

 instance on Roaring Run, south of Watertown, it is clearly seen that 

 the Fusispira beds occupy a considerable thickness, not a few inches, 

 at the top of the Trenton. I have already pointed out above that the 

 typical localities for such of the above species of the Fusispira fauna 

 as were described by Hall are all in the Upper Trenton. 



The Fusispira fauna is, in part, so far as relates to its gastropods at 

 least, a recurrent fauna, which fact has not been recognized by Ulrich, 

 and has led to the erroneous correlation of the Minnesotan with other 

 sections. In jMinnesota Fusispiras make their first appearance in the 

 Upper Trenton, but in other regions they were introduced with the 

 Black River fauna and recurred at various times. Thus in Kentucky 

 one finds in the Wilmore, Fusispira subfusiformis, F. angusta, and F. 

 angusta suhplana, but its associated fauna contains none of the "guide 

 fossils" found with the Fusispiras in Minnesota. There is a large 

 gastropod fauna, but it is not the Fusispira fauna. 



In the quotation from Ulrich above, the Fusispira fauna is said to 

 be at the base of the Trenton in northern Michigan, Ontario, Quebec, 

 New York and northern New Jersey. Of northern Michigan I know 

 nothing. Ontario has already been sufficiently discussed. Where in 

 Quebec the Fusispira fauna is developed I can not imagine, though I 

 have an intimate knowledge of the principal localities for the Trenton 

 of that province. In reply to a request for information. Dr. Ulrich 

 wrote me under date of 12 January, 1912, as follows: "The Fusispira 

 Jauna was found in New York in the vicinity of Poland, Herkimer 



