]\rEMOiR OF ,tosp:ph le c'Onte 53 



yet been shed on it. I bring forward the problem here, not to solve it, for I 

 confess my inability, but to differentiate it from other problems, and especially 

 to draw attention to these movements as modifying the effects of movements 

 of the first kind, and often so greatly modifying them as to obscure the prin- 

 ciple of the permanency of oceanic basins and continental areas, and even to 

 cause many to deny its truth. Nearly all the changes in physical geography 

 in geological times, with their consequent changes in climate and in the char- 

 acter and distribution of organic forms — in fact, nearly all the details of the 

 history of the earth — have been determined by these oscillatory movements ; 



This pheuoineiiun still awaits satisfactory analysis and soluiioii, but is 

 better explained under the planetesimal hypothesis, since this admits of 

 much greater contraction of the globe and of consequent crowding and 

 crushing of the small continental segments between the larger oceanic 

 segments, with consequent warping and buckling of large surface areas, 

 specially along the continental margins, under pressures varying in di- 

 rection and degree. 



In his autobiography Le Conte has given his own estimate of his con- 

 tribution to the world of thought. He seemed to take the most pride in 

 his writings on evolution. His best original work was probably in optics. 

 Concerning geology, we give his own words : 



"In geology, T believe some real substantial advance in science was made 

 in my series of papers: (1) on the structure and origin of mountain ranges; 

 (2) on the genesis of metalliferous veins; (.3) especially in that on critical 

 periods in the history of the earth; (4) on the demonstration of the Ozarkian, 

 or better, the Sierran epoch, as one of great importance in the history of the 

 earth, I might mention several others that I believe are of prime importance, 

 but I am willing to stand by these." 



A suitable close for this memoir is the fine tribute bv Professor 

 Chamberlin.^" 



"With the death of Dr. Joseph Le Conte there has passed away perhaps the 

 hist distinguished representative of the general geologist as typified during 

 the past century. This passing type of the general geologist was a distinctive 

 outgrowth and representative of a transitional stage of intellectual procedure — - 

 a passage from the former mode in which the generalizing and philosophical 

 factors held precedence and the toilsome modes of scientific verification fol- 

 lowed as their servitors, to the present or at least the coming method in which 

 scientific determinations are the basal factors to which generalizations and 

 philosophies are but dependent accessories. Wo owe much of the transition 

 itself to Dana and Le Conte, the two noblest American representatives of the 

 passing type, for while they grew u]) under the influence of the older intel- 

 lectual attitude, they grew out of if in spirit while (lioy steadied and guided 



" I'.illl. fii'ol. Hoc. Ani,, vol. S, p. \22. 



1" RdKorial in .Toiirnal of Geology, vol. 0, inoi, pp. -l."?!) 1 l(t. 



V — Bull. Gkol. Soc. Am., Vol. 20, ini4 



