T. II. Holland — Eock-iceathering and Serpentinization. 541 



These are by no means the impressions T have gathered from 

 Eoth's writings, in which I can find no change of views between 

 1869 and 1893, and nowhere any consolation either for my views of 

 the origin of serpentine or of Professor Rlerrill's modification of them. 

 Eoth ' distinguished ehifache Verwitlerung — the simple chemical 

 reactions produced in rocks by the action of atmospheric air, water, 

 and the contained gases— from comyllcirle Venuittening, which is- 

 due to the complex reactions of solutions formed by the first 

 process. By the use of the term com-plicirtp. Verwilterung Koth 

 merely referred to the complex nature of the chemical reactions, and 

 never suggested that the water of these solutions was other than of 

 immediate superficial origin. The action of superheated water, 

 steam and other vapours from deep-seated sources, Roth distinguished 

 under quite a difi"erent name as Zerselzung, which is unfortunately 

 the term decomposition by which Professor Merrill proposes to- 

 distinguish true weathering from the more deep-seated alteration and 

 hydrometamorphismr 



Moreover, although it is true, as Professor Merrill says, that Rotb 

 in his " Ueber den Serpentin " described the processes and results 

 incidental to the Verwitlerung of the serpentine quite independently 

 of those incidental to its first production, he did not recognize any 

 essential diflerence between them ; but, on the contrary, says 

 expressly, " die Verwitterung des Olivins zu Serpentin nur ein 

 Stadium des Prozesses bezeichnet, der Serpentin unterliegt seiner- 

 seits einer weiteren Verwitterung." " Eoth evidently considered 

 serpentinization to be induced by meteoric waters, and referred 

 definitely to the oxidation as a phase of the process, Both in his 

 first volume, which appeared in 1879 (p. 113), and in the last 

 volume of his " Chemische Geologic" (1893, p. 422), he refers- 

 to the serpentinization of olivine under the heading " Einfache 

 Verwitterung des Olivins." On this account, coupled with the 

 acquiescence by silence or applause on the part of English writers, 

 I brought the new facts obtained in India to the notice of the 

 British Association, and concluded therefrom that atmospheric agents- 

 had practicall}' nothing to do with the formation of serpentine rock. 

 On the same occasion, by comparing the geological history of the 

 Madras Presidency, where fresh olivine rocks occur abundantly,. 

 with that of the Andaman Islands, Kashmir, and Baluchistan, 

 where our serpentines are found, it was suggested, as a basis for 

 discussion, that submergence below sea-level favours the formation, 

 of serpentine. 



^ Allgenieine unci Chem. GeoL, vol. i (1879), pp. 1, 2, 43, 47, aud 159. 



- As results of complicirte Verwitterung Eoth iucluded the zeolites and many of 

 the minerals considered by Professor Merrill to be due to agents of deep-seated origin.- 

 I agree with Professor Merrill's list (serpentine not being on it), but 1 see no support 

 for our views in the writings of Eoth. His Ititer use of the expression agrees exactly 

 with the statements made in earlier papers, where the verb is not given an adjectival 

 form, as in " complicirt sich die Verwitterung des Felsitporphyrs durch Zufuhr von 

 Kalk und Eisen aus nahe gelegenen Partien, so entstehen ' Epidosite ' Gesteine ' 

 (Abhand. der Akad. der Wiss., Berlin, 1869, ii, 133). 



3 Abhand. der Akad. der Wiss., Berlin, 1869, ii, 345 aud 346. 



