PROCEEDINGS OF THE POLYTECHNIC ASSOCIATION. 467 



Islv. Stetson sug^'ested that many silk goods, where strength is 

 unimportant, arc made of waste silk ; and even if this article 

 could not be reeled, it might prove to be valuable. 



Dr. Stevens was of opinion that if kept separate the worms 

 would form cocoons. 



NEW GUN. 



]\rr. Stephen Krom exhibited drawings of a new breech loading 

 guu invented by him, which he explained. 



AMERICAN GEOLOGY. 



Mv. Bowley exhibited a specimen of gold quartz from Nicarauga. 

 There are no more than eight veins in the whole district from 

 which this came. The mine has been worked for three hundred 

 years successfully. The ore will yield 10 ounces to the ton, 

 which is considered remunerating. 



Dr. Stevens, in his lecture on the geology of this continent, 

 gave the history of our mountain ranges. He said : 



I thought it best this evening to introduce the history of our 

 mountains because the close of their history has very much to do 

 with the preparation of the American Continent for the abode of 

 man. 



As the earth began to cool so that solid rock could be formed, 

 upon the supposition that the earth was once a mass of molten 

 matter, the first crust formed would be thin; and a collapse of 

 that crust, towards the centre, forming a large valley, would 

 throw up contiguous to that valley a mountain ridge. The fur- 

 rowing of the earth's crust is the necessary consequence of the 

 subsidence of any portion of it. 



The earliest system of mountains on the North American Con- 

 tinent has been called the Cabotian system, from the discoverer, 

 Cabot. Commencing in Labrador they stretch across the primi- 

 tive American Continent, one branch running southward of Lake 

 Winnipeg and forming the mountains whence spring the head 

 waters of the Mississippi. These mountains were low, scarcely 

 ever elevated more than a thousand feet above the surface of the 

 country, or 1,600 feet above the level of the sea. The next sys- 

 tem of mountains runs at right angles with the first, or north and 

 south, and lies in several different systems. They rise, in the 

 White mountains to about 3,500 feet above the level of the sur- 

 rounding plain. The third system is the Appalachian, beginning 

 in Massachusetts, and terminating in Alabama. If this system 



