79 



carbonic acid, water, silica, alumina and oxide of iron. It 

 differs from pitchblende in its ready solubility in acids ; 

 the uranium existing in pitchblende as U U, the proto-per- 

 oxide, and of course in an insoluble state. He also read 

 analyses of Pectolite from Isle Royale and Bergen Hill, and 

 showed that the Stelliie of Beck from Bergen Hill, as well 

 as the Stellite and Wollastonite of Thomson, ought to be 

 united with Pectolite, since they agreed with it entirely in 

 chemical and physical characters. 



Mr. Desor exhibited a number of Drift fossils from Nan- 

 tucket, which he had collected in company with Mr. E. C. 

 Cabot. They were taken from the cliff at the east end of 

 the island. The outlines of the strata on the surface of 

 this cliff are somewhat obscured by the sand which has been 

 blown over it. About half way up it is an oyster bed, from 

 which the specimens were taken. It contains many fossils 

 in a remarkably perfect condition ; even crab's claws being 

 found here unbroken. Its position indicates that it has not 

 been disturbed since it was formed. It contains most of the 

 species found on the neighboring beaches. Specimens of 

 Venus are sometimes found with the valves open, as if from 

 the relaxation of the muscles at the moment of death. 



Until within two years it has been supposed that there 

 were no fossils in the drift south of Lake Champlain. Last 

 year Mr. Desor discovered a similar fossil deposit on Long 

 Island in Brooklyn, which was then carefully examined by 

 himself and Mr. Redfield. Its origin was very doubtful how- 

 ever, as the shells were very much broken and worn. But 

 at Nantucket, a point between these localities, the formation 

 is now found to exist without the least trace of disturbance. 

 The strata at the east end of this island dip towards the 

 west, the angle of dip gradually increasing from the highest 

 to the lowest. The fossils are of the same species as those 

 now living on the neighboring shore ; an interesting fact 

 indicating a similarity of climate at the time they were de- 



