222 president's address. 



the difficulty which the various instincts present to his theory ; 

 and his attempt to show that the instinct of the hive-hee may 

 have been a gradually-acquired habit, is not the least curious 

 and preposterous chapter of his ingenious work. 



To the hypothesis of the gradual and continued transmission 

 of life from one species to some other form widely different in 

 structure, geology opposes the records preserved in the organic 

 remains of each successive formation. To remove this difficulty, 

 Mr. Darwin has spared no skill and labour for the establishment, 

 first, of the imperfections of the geologic record; and, secondly, 

 of the enormous lapse of time to be allowed for the deposition of 

 each formation, and for the intervals between them. In order 

 to this, he assumes Professor Ramsay's estimate of the thick- 

 ness of the British fossiliferous strata at 72,584 feet, or nearly 

 13| miles. But it seems scarcely fair to take the maximum 

 thickness of each individual deposit in different localities, and 

 sum them for a single total. No geologist maintains the thick- 

 ness of the fossiliferous strata to be in any one place 13 miles. 

 There may be limits even to the length of geologic eras. The 

 Ganges has been computed to pour annually into the sea a 

 sediment sufficient to cover 5,000 square miles for a depth of 

 half an inch. The Amazon, without a delta, must be depositing 

 a far greater mass annually in the depths of the ocean. 



Again, he assumes 300,000,000 years for the denudation of the 

 Weald, supposing the action ^ the water to have been continuous. 

 I think there are considerations which will modify this huge 

 demand on Mr. Darwin's grand reserve of geologic time. First, 

 he does not calculate that the sea would eat away both sides of 

 the Weald at once. This reduces his estimate one-half. Secondly, 

 he assumes that the sea would eat into cliffs 500 feet in height, 

 at the rate of an inch in a century, i. e., that it would work at the 

 rate of a yard in 22 years against a cliff one yard in height. But 

 here he has assumed that the underlying strata would afford the 

 same resistance as the superficial chalk, and he seems altogether 

 to have forgotten the undermining power of the sea's action. 

 Let any observer take the Permian coast of Durham, and watch 

 the excavating power of the waves, and he must indeed multiply 



