46 



mineral character of our Trenton group of rocks at Ottawa is sufficiently- 

 constant to make it a good test almost anywhere within a radius of 200 

 miles, and where the least doubt arises, superposition would be another 

 ready means ; but the Trenton group of Missouri, for instance, is of a 

 beautiful creamy-buff dolomite, very unlike our ugly sad-coloured lime- 

 stone, and here we have to fall back on our fossils for light as to the 

 age of the rock. 



As a proof of the great value of fossils as evidence, I quote the 

 evidence of Dr. Hall, New York State Geologist, given in 1854, before 

 a select committee of the House of Commons of Canada, as follows : — 

 " One of the great practical advantages resulting in New York I con- 

 ceive to have been the proof that no valuable or workable coal exists 

 within the State. This fact, although of a negative character, has for 

 ever set at rest all explorations for coal, while it has been ascertained 

 that during fiftv vears previous to the commencement of the survey not 

 less than one million of dollars had been expended in abortive search 

 for fossil-fuel, where a well-informed geologist would have at once 

 pixmounced the undertaking useless and certain to prove a failuie." 

 Through a study of the fossils it was established that in New York 

 " both salt and gypsum are products of the * * * Silurian Period, 

 while previously it had been believed they belonged to the New Red 

 * * and consequently that coal would be found in these rocks as in 

 Europe * * * The evidence from fossil character soon proved the 

 futility of such an expectation. Thus, in this instance, mineral evidence 

 set the public wrong and fossil evidence corrected the error. Again the 

 occurrence of the rock known as the Oneida Conglomerate was, from its 

 mechanical structure, believed to be identical with the Millstone Grit of 

 England, which underlies the coal, and examinations for coal were * * 

 to some extent made. From the fossils in the rocks above and below 

 it has been proved to belong to the older Silurian beds. Thus, in this 

 case also, mineral evidence misled the public, and fossil evidence cor- 

 rected the error." * * * * 



An instance in which a knowledge of the fossil remains of a 

 formation was of still greater importance than a knowledge of its- 

 mineral character is the lead-bearing formation of the States of 

 Wisconsin, Illinois and Iowa. For many years a serious misapprehen- 



