186 



THE GEOLOGIST. 



glaciers. Another cause — viz. the relative distribution of 

 land and water having great influence on the temperature of 

 the earth — would, for the reason before mentioned, also 

 exercise peculiar influence on the temperature of the ocean. 

 As the temperature of the surface of the globe depends upon 

 solar heat, that land most immediately under the equator 

 absorbing most solar rays must have the greatest influence 

 upon the general temperature of the earth : consequently the 

 smaller the quantity of land within the tropics, the lower 

 would be the temperature of the waters of the ocean. This 

 paucity of land within the equatorial regions is confirmed by 

 the observations of Darwin, who is of opinion that a large 

 portion of South America is of very recent geological origin. 

 So late as the year 1822, no less than 100,000 square miles 

 was raised several feet. Also, in 1819, across the delta of 

 the Indus, a portion of land, 50 miles in length by 16 feet 

 broad, was raised 10 feet ; showing that, even up to the present 

 time, the same causes continue to operate which have elevated 

 a large portion of the tropical regions. 



Although elevating causes are at present confined to equa- 

 torial regions, there is no reason to doubt that they also for- 

 merly operated in higher latitudes. 



That, by this cause, considerable masses have been raised 

 to their present position is undeniable ; yet the universal 

 diff"usion of traces of the ancient ocean having been above its 

 present level about the same geological epoch, as well as the 

 horizontality of elevated sea beaches, and the probability of 

 the temperature of the earth having been at an epoch slightly 

 antecedent to the historical period considerably less than its 

 present average temperature, appear strongly presumptive in 

 favour of a general depression of the surface of the waters of 

 the ocean. 



Mr. E. W. Binney said, the hypothesis started by the 

 author of the paper which had just been read, with respect 



