GEOLOGY. 259 



and Mackinac. From these observations it appears that the mean an- 

 nual temperature of Fort Brady is nearly two degrees lower than 

 that of Fort Wilkins, although the latter post is nearly a degree fur- 

 ther north. This difference arises from the insular position of Kewee- 

 naw Point, which is surrounded on three sides by water. The climate 

 of Fort Brady during the whole season corresponds in a remarkable 

 degree with that of St. Petersburg. The temperature of the region is 

 very favorable to the growth of cereals. The annual ratio of fair days 

 at Fort Brady is 168 ; of cloudy days, 77 ; rainy days, 71 ; snowy days, 

 47. 



The temperature of the water of Lake Superior, during the summer, 

 a fathom or two below the surface, is but a few degrees above the 

 freezing point. In the western portion the water is much colder 

 than in the eastern the surface flow becoming warmer as it advances 

 toward the outlet. 



ON THE AGE OF THE CONNECTICUT RIVER SANDSTONES. 



THE following remarks on the age of the sandstones in the valley of 

 the Connecticut and in New Jersey, were made by Mr. Redfield, of New 

 York, at the Cincinnati meeting of the American Association : 



In the earlier periods of geological inquiry the Red Sandstone rocks 

 of the Connecticut were supposed to be an equivalent of the Old Red 

 Sandstone of England. Resting immediately on crystalline and gneis- 

 soid rocks, and apparently deficient in organic remains, there appeared 

 to be no obvious grounds for a different conclusion. On subsequent 

 investigation, Prof. Hitchcock was induced to class these rocks with 

 the New Red Sandstones of the English geologists. At this period, 

 some fishes and remains of plants had been discovered in the rocks ; 

 but their characters were not then so well understood as to be consid- 

 ered decisive of the geological position. Mr. Redfield alluded to the 

 views of Dr. Jackson, and to a paper read by Mr. Wells at different 

 meetings of the Boston Society of Natural History. He was compelled, 

 by the evidence of fossils in his own collection, to dissent wholly from 

 the views of Dr. Jackson regarding the geological position of the 

 sandstones of Nova Scotia, Maine, Connecticut River and New Jersey ; 

 and was also constrained to dissent from the division of the series 

 which Mr. Wells has attempted to establish. Mr. R. has examined the 

 formation attentively in three States, and does not consider the grounds 

 alleged to be of sufficient validity. The whole extent of this formation 

 in Connecticut has been examined most carefully for a series of years 

 by Dr. Percival, apart from its fossils, and an attentive examination 

 of his Report on the Geology of Connecticut will show that, in the 

 default of zoological evidence, no such separation can be established. 

 The conclusion to which Mr. Redfield had himself been led by these 

 fossil remains was, that the Red Sandstone rocks in which they occur 

 are decidedly of Post-Permian date. They may belong to the Trias- 

 sic group, but appear to have stronger affinities to fossils of the Liassic 

 or Oolitic groups. He submitted to the Association some characteris- 

 tic specimens. 



