20 



HAYDEN : GEOLOGY OF NORTHERN AFGHANISTAN. 



mass to a certain extent, against which the sedimentary formations of 

 the mesozoie and tertiary times were forced and thug laid into the folds 

 which now form the greater area of Central Asia and the fringing 

 ranges north of the Hindu Kush." Since, according to Mr. Griesbach, 

 Tertiary beds are involved in this folding, the age of the postulated 

 korst 1 need not be greater than late Cretaceous or early Eocene, and it 

 will be shown below (p. 22) that at least part of it was submerged 

 during the Triassic period. 



The metamorphic area extends from Kabul for considerable dis- 

 tances in all directions. On the south Mr. Griesbach found hornblende- 

 and mica-schists and crystalline limestone, often associated with 

 igneous rocks, in Logar, Kharwar, Khurd Kabul and in the upper 

 valley of the Surkh-ab. The metamorphic series is associated, in some 

 manner which is not quite clear, with a grey limestone which Mr. 

 Griesbach referred to the Mesozoie group and which is extensively 

 developed in the neighbourhood of the Shutargardan massif, and 

 extends along the southern flanks of the Safed Koh (13, 74). To the 

 south-west of the Shutargardan the same metamorphic series is largely 

 developed in Kharwar, where the secmence is said to be the same as that 

 of the Siah Koh (13, 77). 



1 In Mr. Griesbach's view this was a continental area of old crystalline rocks, and 

 is not to be confused with the deep-seated horst which has recently been placed by 

 Professor Joly on the geological Index exptcrgatorius. This is presumably the 

 " Archtean Buttress " inserted on Dr. Oswald's map referred to above (footnote, p. 9). 

 From my description of the Khingil series (p. 22), it will be seen that much of this 

 supposed " Buttress " is composed of marine Trias of Himalayan type. The difference 

 in direction between the lines of folding of the Hindu Kush and those of the Safed 

 Koh does not require the postulation of any intervening obstacle, for their respective 

 trends are only such as would be expected from the nature of the syntaxis of the 

 Himalaya with the mountains of Afghanistan, resulting in a curve convex to the 

 north, and produced apparently by the lapping of the southward-moving folds around 

 a projecting cape of Gondwanaland. The area occupied by this so-called buttress has 

 never been visited by a geologist, and consequently we have no direct evidence as to 

 the nature of the rocks of which it is composed, but from such observations as I was 

 able to make from neighbouring bills, I have little doubt that it embraces partly the 

 easterly continuation of the rocks of the Kabul plain and partly beds similar to those 

 of the Paglimau and Hindu Kush ranges, whilst direct observations show that some 

 of the hills are capped by the comparatively young rocks of the Khingil series. 



