63 



quarries at Amherstburg as well as at several points in 

 Michigan, it is found that a series of formations lies between 

 the Onondaga and the top of the Salina. American 

 geologists propose to include all these layers in the Monroe 

 formation and to ascribe them to the Silurian. The 

 Monroe formation thus defined is divided into an upper 

 and a lower division by the Sylvania sandrock. 



Glaciated surface of Onondaga limestone showing the deflection of the ice around 

 included corals, south end of Pelee island. Lake Erie, Ontario. 



Amherstburg — Alt.: 593 feet; 180-27 m - Amherst- 

 burg, near the mouth of the Detroit river, is one of the 

 historically important points in western Ontario: its origin 

 during the French regime is attested by the names of many 

 of the present inhabitants. The first white men to ascend 

 the Detroit river were LaSalle and Hennepin, who made the 

 Amherstburg passage in 1679 in the ' Griffin." Since 

 this time, $12,000,000 have been spent by the American 

 government to improve he route. The necessity for this 



