The Gneissose- Granite of the Himalayas. 353 



cases in which " lamiaated gabbro " was, in deference to this prin- 

 ciple, written down as a sedimentary rock ! ^ 1 trust we have now 

 nearly heard the last of arguments which may fairly be paraphrased 

 into such a remark as — "This is a striking case of dynamo- 

 metamorphism. It is quite evident that the rock was deformed by 

 tremendous earth movements after its solidification, because it shows 

 flaser structure and crushing, and some of its minerals have been 

 drawn out into strings." 



Turning again to Mr. Middlemiss's Memoir, there are some facts 

 in it which, to my mind, raise difficulties in the way of the 

 acceptance of the theory advocated by the author, and suggest 

 the existence of evidence against it. Mr. Middlemiss tells us at 

 page 75 of basic dykes which generally " form narrow bands or 

 dykes roughly parallel to the foliation of the intruded rock " ; but 

 " in certain places the dykes cut across both the schistose series and 

 the gneissose-granite intrusions, and also send off small veins into 

 them." With the exception of the Indus Valley dykes, nothing is 

 said about the foliation of the basic dykes that cut across the 

 foliation of the schists. Are they foliated or unfoliated, and if 

 the former, is their foliation parallel or at an angle to that of the 

 schists? In fig. 4 (p. 76) one of the Indus Valley dykes is repre- 

 sented, and parallel fine white lines are to be observed along one 

 edge of the dyke which af)pear intended to represent foliation. If 

 these lines are intentional, and not an accident in printing, it is to 

 be observed that they are at a high angle to the foliation of the 

 schists and only occur along one margin of the dyke. 



The author tells us (p. 75) that the dykes which cut through 

 the gneissose-granite of the Indus are foliated along their edges. 

 No information is given as to the direction of this marginal foliation 

 in relation to the foliation of the granite ; but it seems clear that 

 the conditions under which the foliation was impressed upon the 

 two rocks must have been different. If the foliation were imparted 

 to the granite after its solidification, and after the intrusion of 

 the dolerite, it is difiicult to understand why the dolerite was not 

 foliated from side to side. 



In the detailed account of the Indus Valley section given in the 

 Memoir (p. 253) a mass of dolerite is shown in fig. 51, as an 

 intrusion in the schists parallel to their bedding. The section 

 suggests the idea that the dolerite was folded up with the strata, 

 and that the latter form a somewhat crushed anticlinal. The two 

 dolerite bands on the right of the illustration might even represent 

 the dying out of the dolerite seen on the left of the woodcut. 

 The schists and the granite seen in this section appear from the 

 author's general remarks (see ante, p. 346.) to be foliated in a direction 

 parallel to the folds of the bedding; but the dolerite, which was 

 apparently folded up with the schists and the granite, and must 

 have participated in the stress, crush, and shearing, which accom- 

 panied the folding of the rocks, is absolutely without foliation. If 



1 "This gabbro," he writes, "was formerly regarded as a later sedimentary 

 series ! " (Loc. cit., p. 708.) 



DECADE IV. VOL. IV. — ;N0. VIII. 23 



