6 McMahon 8f Htidleston — 



their discoverer, " that is very peculiar and characteristic, and which 

 can be traced without any doubt to great distances." Mr. Medlicott 

 adds : " This band promises to be of special utility in identifying 

 rocks in the interior, with those of the outer parts of the lower 

 Himalayan region." 



The principal members of the group are the conglomerate and 

 the limestone. The conglomerate appears below the limestone ^ in 

 the Simla area, and this sequence is that observed in the Chitral region. 



Mr. Medlicott, in his description of the typical Blaini area,^ notes 

 that " as an irregular accompaniment of these Blaini beds " (namely, 

 the conglomerate and limestone) " I must mention a clear coarse 

 quartzite : at two or three points in the lower course of the Blaini, 

 this bed shows apparently over the limestone." In the Blaini river 

 this " irregular accompaniment " " apparently " occurs above the 

 limestone, but in the Chitral region a red sandstone appears below 

 the limestone. The Chitral red sandstone therefore cannot be 

 a lateral extension of the particular beds seen at Simla ; but as 

 Chitral is about 450 miles distant as the bird flies from the Blaini 

 river, it is hardly a matter of surprise that the local conditions 

 of the two places should not have been precisely alike during the 

 Blaini age, and that arenaceous deposits should have been laid down 

 at slightly different horizons at Chitral and Simla. 



The red sandstone bed of Chitral, which is associated with 

 a limestone, has been detected in several places in the Gil git area, 

 and has been described in my paper on that region.^ As the red 

 colour of this bed naturally strikes the eye of an observer, the bed 

 may prove valuable in leading to the identification of the group 

 of which it is a member in adjoining areas. 



My son did not detect the Blaini conglomerate in the Gilgit area, 

 but as his attention had not then been directed to this rock, he 

 thinks it possible that it may hereafter be found in that region. 

 He thought at the time that the conglomerates he came across were 

 probably of glacial origin. It may, moreover, be a work of con- 

 siderable difficulty to detect the Blaini conglomerate in the Gilgit 

 area, if it occurs there. Gilgit is a region of intense metamorphism, 

 and the conglomerate may there be metamorphosed almost out of 

 recognition. Even in the comparatively unaltered area of Dalhousie, 

 the conglomerate has become schistose and foliated.* Moreover, the 

 pebbles imbedded in the matrix of the conglomerate are sometimes 

 locally very sparse ; and when this is the case, the difficulty of 

 detecting the rock in a highly metamorphosed area would be 

 greatly increased. 



My son's description of the Chitral conglomerate corresponds 

 with the appearance of the Blaini rock in many places in the 

 Simla and Dalhousie districts. The pebbles of the Chitral con- 

 glomerate are more or less rounded, and vary much in size and 



1 Medlicott: Memoirs G.S.I., 1865, vol. iii, p. 30. McMahon: Eecords G-.S.I., 

 1877, vol. x, p. 207. ^ Loc. cit., p. 31. 



3 Q.J.G.S., vol. Ivi, p. 358. 

 * McMahon : Eecords G.S.I., 1881, vol. xiv, p. 306. 



