ROCKY MOUNTAIN MEDICAL ASSOCIATION. 25 
America is frequently spoken of as the "New 
World," but geological evidences render it probable 
that it is among the oldest of the continents. The 
rocks of Canada are at least as ancient as any exposed 
in Europe. Too little is known of the geology of Asia 
to enable me to speak of it. Professor Agassiz said, 
"Geology finds its oldest landmarks in America.'"^ 
man back to the Lower Miocene times. In the records of the Geo- 
logical Society of India for 1873, Medlicott gives an account of a 
quartzite implement, precisely of the same class as those found in 
Southern India, which was discovered in the deposit of the Narmada 
Valley. The late Dr, Falconer regarded these deposits as Pliocene, 
while Medlicott places them with the Pleistocene. In India, man co- 
exists with the Elephas insignis, Bos, and Hippopotafmis noviadicus. 
Lubbock, in Nature, March 27th, 1873, communicates the information 
that mastodon bones having figures of animals etched upon them were 
found in beds regarded as Miocene Tertiary. From these and other 
recent discoveries it is rendered probable that the appearance of man 
goes back to the middle of the Miocene period. [American Journal 
of Science, vol. 5, p. 497.) 
The Laurentian range of mountains in Canada exhibits the oldest 
metamorphic rocks that have been discovered. As corroborative of 
he view of the great antiquity of the American continent. Sir Charles 
Lyell estimates that the Mississippi River has been running in its 
present bed for 100,000 years. Professor Huxley, in estimating the 
time required for the Niagara River to have cut its channel from Lew- 
iston to the present falls, indorses the opinion of Lyell that it could 
not be less than 60,000 years, and may have required much longer. 
Dr. Bennett Dowler, of New Orleans, discovered four successive tiers 
of deposits, each with growth of cypress trees, one overlying the other, 
in the alluvium of the delta of the Mississippi River, which he esti- 
mated would have required 57,600 years for their production. Indian 
bones and pottery were found beneath the roots of some of the cypress 
trees exhumed in sinking pits for the gas-works at New Orleans, 
at a depth which he estimated would have required 15,000 years lo 
have filled up and the trees to have grown from the time they were 
placed there. Fossil remains of air-breathing animals are found in 
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