262 ANNUAL OF SCIENTIFIC DISCOVERY. 



ilar deposits to those on Lake Champlain are found on Lake Ontario, 

 at a level 80 feet lower. Mr. Desor has thus been led to the opinion, 

 that the sea had once filled the St. Lawrence, Lake Ontario, and Lake 

 Champlain, being- bounded on the east by a barrier along Lake Cham- 

 plain. As the deposits in these localities do riot in the opinion of the 

 geological party to which he was attached belong to the true drift, 

 they had proposed for them the name Lawrencian deposits, and he 

 hoped the term would be accepted by geologists generally. 



Prof. Rogers remarked, that throughout New England, on the river 

 courses, and on the St. Lawrence, there are found strata of thin, lam- 

 inated clays and sands, which had evidently been tranquilly deposited. 

 During a visit to the Green and White Mountains, the past summer, 

 he had seen these layers at an elevation of 1,000 feet above the sea, 

 following the outline of the country, and not containing marine shells. 

 He thought it improbable that there had been the coincidence of an 

 elevation of these strata with the mountains and ridges where they 

 are found. He thought it more philosophical not to suppose the for- 

 mer existence of the sea beyond the point where marine fossils have 

 yet been observed. As to the strata of the White and Green Moun- 

 tains, they were not entirely explicable, but they may have been the 

 result of an extensive drainage. The name offered by Mr. Desor he 

 was very ready to receive, as applicable to a local deposit. Proceed- 

 ings of the Boston Society of Natural History. 



ORIGIN OF THE GREEN-SAND OF NEW JERSEY. 



AT a Meeting of the Boston Society of Natural History in Febru- 

 ary, Prof. Rogers presented a theory to account for the origin of the 

 green-sand of New Jersey. This sand is found under the microscope 

 to be sharp on its edges, and not rounded, or showing any signs of 

 attrition. It is in the form of small granules, like grains of gun- 

 powder, of a dark olive, sometimes greenish color, from the presence 

 of protoxide of iron. It contains silica, about fifty per cent. ; pro- 

 toxide of iron, twenty; alumina, seven; potash, ten; lime and water. 

 From its physical characters, Prof. Rogers was inclined to regard it 

 as an original deposit. Had it been of mechanical origin, it would 

 have contained conglomerates and been mixed with other minerals, 

 which is not the case. Neither is there any green rock known from 

 which it could have been derived. His theory was, that at the time 

 when the southern part of the United States was submerged, the 

 green-sand was deposited from the Gulf Stream. The water he sup- 

 posed to have been charged with soluble silicates of volcanic origin 

 somewhere at the South, perhaps in the region of the West Indies, 

 which were precipitated as the current reached the cooler latitudes of 

 the North. Dr. C. T. Jackson said he agreed with Prof. Rogers in 

 his explanation of the green-sand deposit. The process would be 

 similar to that of the drying of French green. He suggested ther- 

 mal springs as another source from which such a deposit might be 

 derived. 



