W. N. Benson — Origin of Serpentine. 707 



(Grubenmann 1910). The extremely interesting dis- 

 cussions recorded in "The Genesis of Ore Deposits" 

 (Posepny Memorial Volume) show, however, that, in the 

 opinion of several authorities, Beck, Launay, Lindgren, 

 Eickard, Yogt and others, Van Hise has under-estimated 

 the contribution made by magmatic waters to the general 

 underground circulation. 



Holland (1899) has given a very special form to the 

 hypothesis of the production of the great masses of ser- 

 pentine by circulating epigene waters. While admitting 

 the local action of magmatic carbonated siliceous waters, 

 he points out that in the great geosynclinal regions of the 

 world, the peridotites are almost always completely ser- 

 pentinized, while in the continental massif of Peninsular 

 India they are almost anhydrous, except for those parts 

 that have been attacked by local magmatic waters (the 

 evidence of this last is discussed below). From this he 

 concludes that it is probable that advanced serpentiniza- 

 tion results from an enhanced water-circulation brought 

 about by the immersion of the land area beneath the sea ; 

 "for if serpentinization is due to water coming from con- 

 siderable depths, it is difficult to see why these rocks, 

 erupted at different times, and in widely separated local- 

 ities in Peninsular India, should universally escape, 

 whilst in other areas, other serpentines also widely separ- 

 ated by great distances, serpentinization is so constant. 

 "With the evidence of the action of deep-seated vapours in 

 other ways in Peninsular India, the value of this point 

 becomes accentuated. ' ' But he adds: "Although the 

 evidence, both positive and negative from India, indicate 

 that a submarine existence has at some stage formed part 

 of the history of every serpentine-mass, it will require 

 the testimony of other areas to show that such submarine 

 conditions are essential for serpentinization on an exten- 

 sive scale." 



The hypothesis is one that it is almost impossible to 

 test satisfactorily. Holland draws attention to the belt 

 of ultrabasic rocks on the eastern side of the United 

 States, which are serpentinized in the northern portion 

 over which the sea has transgressed at various times, but 

 are practically anhydrous in the southern portions, pre- 

 sumably crystallized under the same condition but which 

 he believed were never covered by the sea. Schuchert's 

 recent series of paleogeographical maps (1910) confirm 



