364 lietjt.-gen. c. a. mcmahon on [May 1900^ 



If I am correct in correlating the limestones of Gilgit with the 

 Carbo-Triassic Series of Kashmir and the North-western Himalaya* 

 it follows that the micaceous slates, schistose rocks, and 

 grits that lie above the limestones cannot be older than 

 Triassic, and may be of younger age. The metamorphism 

 that they have undergone is slight, and is easily accounted for by the 

 intrusion of granite and by the pressure that tilted them into a 

 vertical position. 



It also follows, from this correlation, that the schists below 

 the limestones are presumably of Lower Carboniferous 

 or Silurian age. They have all suffered from great pressure 

 and from profuse granitic and dioritic intrusions, and these igneous 

 intrusions are amply sufficient to account for the metamorphism 

 that they have undergone. Even in the Satlej Valley pressure and 

 the neighbourhood of granite have converted many of the volcanic 

 rocks into hornblende-schists. 



I now pass on to offer a few remarks on the age of the 

 eruptive rocks. The oldest granite in this area is the Baltit 

 Hornblende-Granite, but as it is intrusive in the grits above 

 the limestone-series, it must, for the reasons above given, be 

 younger than the Trias. 



The next in order of time is the Hatu Pir Granite. It is intrusive 

 in the Baltit Hornblende-Granite, in the limestones, in the foliated 

 diorite of Gilgit, and in the grits of the Darkot Pass. The normal 

 Hatu Pir Granite was followed by the acid variety of this granite. 

 The acid variety is intrusive in the normal Hatu Pir Granite and 

 in the Gilgit diorite. 



The Askurdas Muscovite-Granite is intrusive in the limestones, 

 in the Hatu Pir Granite, and in the Lecher Pyroxenite. It seems 

 probable that this rock, as well as the acid Hatu Pir Granite, 

 represents a late phase of the Hatu Pir eruption ; indeed, I am 

 disposed to think that all the Gilgit granites emanated from one and 

 the same igneous reservoir, and represent successive stages in its 

 history. 



Last of all come the aplites, which appear as veins in the limestone 

 and are probably of Hatu Pir age. 



The pyroxenite and diorite of the Gilgit area seem to have been 

 erupted at intervals during the different phases of the Hatu Pir 

 eruption, which apparently occupied a very considerable period 

 measured in years. Thus the pyroxenite between Eamghat and 

 Julipar is intrusive in the Hatu Pir Granite, but is itself traversed 

 by the Askurdas Muscovite-Granite. The diorite also sometimes 

 cuts through granite, and in other places is cut through by 

 granite. 



As the oldest granite is intrusive in the youngest rocks of this 

 area, its precise age cannot be determined ; all that can be said is 

 that it is of post-Triassic age. 



Several of the granites mentioned in this paper exhibit structures, 



