101 



lake. In the immediate vicinity of the town the elevation 

 is about 850 feet (259 m.) in which the following geological 

 succession is presented: — 





THICKNESS. 



SILURIAN. 



Feet. 



Metres. 



10-Lockport dolomite 



75 



35-40 



15 



235 



50 



190 



175 



50-55 



25 

 ? 



22-8 



9-Cataract shales ' 



IO -6-12 





4"5 



ORDOVICIAN. 



6-Richmond grey shales and limestone. . . . 

 5-Lorraine shales and arenaceous limestone. 

 4— Eden shales 



71. 1 

 15-2 



57-7 



53 " 2 



152-16. 7 



7-6 



? 



3-Utica shales (Upper Utica) 



2-Collingwood shales (Lower Utica) 



i-Trenton limestone (at water level) 



Trenton formation. — The upper Trenton limestone 

 (Hormotoma zone) is exposed on the shore line a short 

 distance west of Collingwood. The strata are of little 

 vertical extent, but they are rich in the fossi.'s characteristic 

 of the upper zone of the Trenton. The more common 

 species are as follows : — 



Corals — 



Streptelasma sp. 



Brachiopods — 



Cyclospira bisulcata (Emmons). Abundant. 

 Dalmanella testudinaria (Dalman). Abundant. 

 Hebertella bellirugosa (Conrad). Rare. 

 Lingula cobourgensis Billings. Abundant. 

 Lingula sp. 



Platystrophia biforata (Schlotheim) . Rare. 

 Plectambonites sericeus (Sowerby). Abundant 

 Rafinesquina alternata (Emmons) . Abundant. 

 Rafinesquina alternata nasuta (Conrad). Abun- 

 dant. 



