GEOLOGICAL HISTORY OF AFGHANISTAN. 



75 



quartzites of the Helmand series bear witness to the proximity of a land- 

 surface undergoing denudation. On the whole the conditions during 

 the Dravidian era in the area represented by the Hindu Kush and Koh- 

 i-Baba were not unlike those prevailing at the time in the Tibetan zone of 

 the Himalaya and the same sea probably covered both areas. This latter 

 suggestion, however, must remain to a great extent hypothetical until 

 fossils have been found in the Kalu series. The small fauna from the 

 Hajigak limestone has been sent to Mr. P. R. Cowper Reed, who has 

 kindly undertaken to describe it and its affinities have not yet been 

 determined. 1 In his valuable paper recently published on the subject of 

 pre-Carboniferous Life-Provinces (24), Mr. Reed has discussed in consi- 

 derable detail the relationships of the Indian and Burmese Devonian 

 faunas and his conclusions would lead us to expect one of European type 

 in Afghanistan. Devonian fossils have been found in Chitral between 

 Drosh aud Mastuj and again on the Baioghil pass, and it would appear 

 that the Devonian sea which covered Bamian and the Hindu Kush 

 extended through Chitral into the Himalayan region and thence, through 

 Spiti and Byans, into Eastern Tibet and Burma. 



Of a Middle Carboniferous fauna we have no record in Afghanistan, 

 for the Helmand series has yielded no fossils, but the latter part of that 

 period and probably also the Permian, is represented in the Khingil 

 series of the Kabul area and by the Pusulina limestone of the Hindu 

 Kush. The Fusulina limestone is of particular interest, since it serves 

 to link the history of Afghanistan with that of many other parts of 

 Asia. The relationship of the fauna to those of similar limestones in 

 other parts of the world has been discussed in a previous paper (17, 252) ; 

 it shows affinities with the Urals on the one side and Texas on the other, 

 whilst the intervening gap is filled by species occurring in Sumatra, 

 Indo-China, China and Japan. Burma has recently been added to this 

 list and I am informed by Mr. La Touche that amongst his collections 

 from the Northern Shan States, which were sent for description to 

 Professor Diener, 2 the commonest species from the Fusulina limestone 



1 See footnote to p. 24. 



2 Professor Diener's interesting description of these collections is now in the press, 

 and will be published in the Palceontologia Indica. 



