GEOLOGY. 299 



indicating the existence over the eastern half of the North 

 American continent, during great intervals of Paleozoic time, 

 of o-eoirraphical and climatic conditions similar to those of 

 Western Europe in later periods. These conditions imply 

 a great mountain -elevation in the present North Atlantic, 

 which would make a desert of the lands of Northeastern 

 America, and which was the Palse-Atlantis {Record for 187V, 

 p. 179). 



In this connection Dieulefait points out that the presence 

 of borates in saliferous deposits is explained by the fact that 

 the waters of the Mediterranean hold in a cubic meter not 

 less than two decigrams of boracic acid, which accumulates 

 in the bittern until after the deposition of the double potas- 

 sium-salt, carnallite. To the action of subterranean heat on 

 the borates of the Tertiary salt deposits of Tuscany he ascribes 

 the boracic acid of the suffioni of that region, as long since 

 taught by Hunt. The latter has called attention to the fact 

 that the gypsum so abundant at the outcrop of the Salina 

 formation was found, in the deep borings of 1170 feet and up- 

 wards, at Goderich, Ontario, to be replaced by anhydrite, 

 which readily changes into gypsum when placed in contact 

 with water. He has suggested that the great pressure at 

 such depths may have dehydrated the sulphate of lime of the 

 originally deposited gypsum, effecting its conversion into an- 

 hydrite, an hypothesis which it would be desirable to test by 



experiments. 



GEOLOGY OF INDIA. 



In addition to the facts already given as to the geology of 

 the Salt Range in Northwestern India, it may be added that, 

 while the rocks of the higher Himalayas are described as 

 syenitic gneiss, they are succeeded by various crystalline 

 schists and greenstones, including silky slates decaying to a 

 white clay. In the conglomerates of the sandstone overly- 

 ing the salt-beds, and also through nearly all the formations 

 below the Himalayas, there occur boulders and pebbles of 

 crystalline rocks, which are described as being unlike those 

 of the northern mountains, and as pointing to the existence 

 of an ancient land-area to the southward. This, according to 

 Wynne, may have been a part of the old tropical continent 

 to which the name of Lemuria has been given, and which, so 

 late as the Tertiary, is supposed to have connected the present 



