302 THE CANADIAN NATURALIST. [Jan. 



southern shore of Lake Superior. Some of these show an 

 astonishing amount of instinct in the way of engineering. Trees 

 many feet in diameter have been cut down by them ; canals are 

 often constructed from their ponds to the localities of the trees on 

 the bark of which they feed — in one instance the canal measuring 

 over 60 yards in length. Natural obstacles are overcome by 

 means of bridges, tunnels, etc., built with great ingenuity. 



On the metamorphosis and distortion of Pebbles in 

 Conglomerate ; by C. H. Hitchcock, State Geologist, 

 Vermont. — Geologists have noticed that in certain highly 

 disturbed localities, when a band of conglomerate can be traced 

 from its normal position to that in which it is contorted and 

 folded, the undisturbed stratum is simply a loosely cemented gravel 

 with rounded pebbles, while in the plicated rocks the pebbles are 

 distorted and flattened. Examples of this occur at Middleton, R. 

 I., Plymouth, Vt., Nagelflue, in Switzerland, and the Permian 

 conglomerate in England. The pebbles are not only distorted, 

 but often changed in their chemical composition, impure lime- 

 stones or schists being displaced by quartz, and probably the 

 original sandstone and conglomerate changed into schists, gneiss, 

 and granite. Prof. Hitchcock thinks that both the metamorphism 

 and warping are due to the agency of infiltrated water under 

 enormous pressure. 



On the Loaver Silurian Brown Haematite Beds op 

 America; by B. S. Lyman. — Thirty exposures of the four beds 

 of this ore have been studied in Western Virginia. Of these, 

 three or four show the solid bed ; the others only have weathered 

 boulders of the ore, mixed with other detrital matter. In 

 comparing these with other Brown Haematite deposits in the 

 United States, the author infers that the lumps of ore, sometimes 

 found mixed with the debris of other rocks, mark the proximity 

 of beds of the Haematite, from which the blocks have been 

 separated by denudation. From the frequent occurrence of 

 carbonate of iron, he regards this as the original composition of 

 the ore, — the carbonic acid having been driven off by heat, or 

 other causes, and the protoxide changed to a sesquioxide. 



Explanations of the Geological Map of Maine ; by 

 Prof. C. H. Hitchcock. —The author showed the large 

 geological map, which embodied the results of work done by the 

 State Survey during 1861-62, and called attention to several 

 points of interest settled during that period. 



