THE OTTAWA NATURALIST 



Vol. XXXI. JUNE-JULY, 1917. Nos. 3 and 4. 



THE TRENTON FAUNA OF WOLFE ISLAND, ONTARIO. 



By Kirtley F. Mather, Queen's University, Kingston, Ont. 



West of the Frontenac axis in Ontario, the most easterly' outcrops 

 of Trenton limestone are those on Wolfe Island at the foot of Lake 

 Ontario between Kingston, Canada, and Cape Vincent, New York. 

 The strata exposed there are the northward continuations of the 

 Ordovician rocks of northern New York and present quite a different 

 succession from that in the Ottawa Valley. It is evident that the 

 Frontenac axis even in mid-Ordovician time was sufficiently defined 

 to influence the boundaries of land and sea. 



The Trenton limestones on Wolfe Island rest upon somewhat 

 similar formations of Black River age. All dip at a very low angle 

 toward the southwest. The contact between Trenton and Black River 

 strata is not exposed but is probably similar to that in the Cape 

 Vincent-Watertown district, a few miles to the southeast in New York 

 State. A distinct unconformity is there indicated* by the presence of a 

 basal conglomerate and an irregular contact. Disconformity is strongly 

 suggested on Wolfe Island by the marked change in fauna between 

 the Black River limestones along the north shore and the Trenton 

 strata which outcrop in the interior and along the southern shore, t 



Prasopora simulatrix orientalis, Pachydictya acuta, Dalmanella 

 rogata, and Rafinesquina alternata are the ubiquitous and characteristic 

 members of the local fauna. They indicate its alliance to that of the 

 "Prasopora zone" or true Trenton as that term is used by Raymond. $ 

 The fauna at hand has little in common with that of the Hull forma- 

 tion in Ottawa Valley or of the Glens Falls limestone in Mohawk 



*H. P. Cushing, Geology of the Thousand Island Region; N. Y. State 

 Mils. Bull. 145, p. 91, 1910. 



fSee geologic map by M. B. Baker, The Geology of the Kingston district; 

 Ontario Bureau Mines, vol. 25, pt. 3, 1917. The Wolfe Island Trenton is de- 

 scribed by E. M. Kindle in Appendix T. of the same report. 



%P. E. Raymond, The correlation of the Ordovician strata of the Baltic 

 basin with those of eastern North America: Bull. Mus. Comp. Zool., vol 56, 

 p. 255, 1916. 



