GEOLOGICAL EXTERMINATIONS. 181 



the continent of Europe in post-Pliocene times, I believe, which must 

 have swept away the whole of its mammalian life. He connected 

 this with the traditional Deluge, and I suppose the tens of 

 thousands of mammoths and mastodons whose remains have been 

 found in some cases frozen, and the flesh in a perfect state of 

 preservation, must have perished suddenly and probably in 

 connection with the same event. 



I quite agree with the author that the mere elevation of the 

 earth's surface will not account for these events. 



Dr. Walter Kidd, F.Z.S. — Without being a geologist, I desire 

 to point out that this important subject of geological exterminations 

 has considerable bearing upon current and unsolved problems in 

 biology. The exclusive sway of selection in the production of new 

 forms of life has received of late years strong support from Darwin's 

 greatest follower, and Weismann has summed up his own life's work 

 in two volumes, The Evolution Theory, in which he has elaborated 

 further his theory of germinal selection invented ten years ago, so as 

 to rehabilitate the doctrine of Darwin's natural (personal) selec- 

 tion. He has finally declared, after great study of the matter, that, 

 Lamarckism is a delusion, and that acquired characters are not 

 transmissible. This sweeping doctrine is intimately connected with 

 our subject of to-day thus : granting that evolution or modification 

 of species has taken place through the ages of geology, this must 

 have come about in one of three ways — either by direct modification 

 of the organism by its environments and use of function — or by 

 selection alone, — or by the combined actions of selection and use — 

 inheritance and direct environmental action. Weismann is forced 

 to allow that among unicellular organisms environmental influence 

 is supreme, but maintains that when multicellular organisms arose 

 and amphimixis (or the mingling of two streams of heredity from two 

 parents) occurred, the influence of environments and use and disuse 

 in evolution abruptly ceased, and that at this dividing line in the 

 history of the organic world selection remained in unquestionable 

 predominance, and that selection is even anterior to the birth of 

 the organism, for it begins in the germ. The fact shown to-day, in 

 the paper before us, that exterminations on a vast scale have con- 

 tinued through geological history by reason of changes of atmosphere, 

 water and soil, is a glaring contradiction to this pan-selectionist 

 theory of Weismann. These exterminations are, many of them at 



