310 Lieut. -General C. A. McMahon — 



If this surmise should prove correct, the appearance of the granite 

 could not be dated earlier than the Carboniferous period, and it might 

 be much younger. 



As regards the subheads (h) and (c) ante : (6) is a mere expression 

 of opinion and calls for no comment; while I need only say with 

 reference to (c) that the only evidence given in proof of the author's 

 contention that the Tanols were derived from the gneissose-granite 

 is that the Tanol beds are composed of coarse-grained quartzo- 

 felspathic material (p. 239). So also is the Torridonian Sandstone 

 of Scotland ! The fact relied on proves no more than that the 

 Tanols were derived from a granite. I and other writers have 

 heretofore held that an ancient granite, or gneiss, was suiFering erosion 

 in, or adjoining, the Himalayan region in Paleeozoic times. This 

 theory is highly probable in itself, and has cogent facts to support 

 it. The author's view that this ancient granite was the gneissose- 

 granite itself is not proved by the fact that all the granite the 

 author has himself seen is of one kind. My own experience led 

 to a different conclusion — a conclusion adopted by Strachey and 

 other observers. The contention that all the granite of the Himalayas 

 is of one age has yet to be proved. 



The author's fourth point is the probability that " the volcanic 

 rocks of Kashmir (the amygdaloids) of about Silurian age are 

 subaerial representatives of the granitic cores" (p. 278). 



"What this opinion is based on T do not know. At present the 

 only petrographic determination of the Kashmir traps with which I 

 am acquainted is the reference to them by Mr. Lydekker,^ based on 

 a note by myself on specimens collected by him. These samples, 

 however, were so altered by aqueous agencies that a determination 

 of the rock species, I stated, would, if made, "bo to a large extent 

 guesswork." Subsequently I made a rather complete collection of 

 the traps on the Chamba border of Bhadarwah, a subdivision of the 

 territory under the Eaja of Kashmir, which was published in 1885.^ 

 These traps consisted of altered basalts, basalt porphyry, andesites, 

 felsites, and volcanic ash. 



Mr. Lydekker, in his memoir above referred to, tells us that one 

 of his specimens contained oi'l and another 62-9 per cent, of silica. 

 The Kashmir specimens, therefore, would appear to be altered lavas 

 belonging to the basic and intermediate classes. So far as the 

 published evidence goes, there seem to be no grounds for considering 

 the lavas of the Kashmir Valley to be the surface representatives 

 of the gneissose-granite of the Himalayas, and the idea of determining 

 the age of the granite by the age of the Kashmir lavas is, to say 

 the least, premature. 



Lastly, the author (p. 277) relies on the following facts : — 



(a) The Trias limestone in Hazara is unnietamorphosed. 

 (6) The Infra-Trias of Hazara is metamorphosed in a " minor 

 degree " as compared with the " Slate " series. 



(c) The metamorphism of the Infra-Trias is attributed to the con- 

 tact action of basic dykes. 



1 Memoirs G.S.I., xx (1883), p. 218. ^ Eecords G.S.I., xviii, p. 93, 



