1887.] Address. 77 



The oilier great formation, the Vindhyan, is still unexplained, no 

 trace of a fossil having, as yet, been found in it. There is a mighty 

 gap between it and the next succeeding Gondwana deposits, and every 

 step taken by geologists seems to make it more difficult to draw any 

 marked general stratigraphical separation between it and the old tran- 

 sition rocks. In one place, it may show apparent sequence or slight 

 unconformability with strata that elsewhere are completely discordant 

 beneath it. Whoever discovers a fossil in the Vindhyan system will 

 assuredly rank as a discoverer who has done good service to Indian 

 Geology. 



We may now proceed to notice the recent work of Indian geolo- 

 gists, mostly members of our Society, beyond the frontiers of India. 

 Mr. Griesbach has recently returned after his two vears' travel with the 

 Afghan- delimitation Commission. From Quettah to the Siyah Koh, 

 Doshakh range, south of Herat, he only found cretaceous (Hippurite 

 limestone) and tertiary rocks, with local profuse intrusions of syenitic 

 granite and basic trap, the same as he had previously described east 

 and west of Kandahar. In the Doshakh range, he came upon a core of 

 carboniferous prodnctus-limestone, and, flanking it on the north, a 

 great plant-bearing series with fossils of Gondwana types, passing up 

 into marine Jurassic strata, succeeded by a great thickness of cretaceous 

 and tertiary deposits. The Paropamisan range to the north of Herat 

 is mostly composed of these permo-trias and Jurassic formations, with 

 intrusions of igneous, rock, granite, and melaphyres, the same stretching 

 north-westwards into the mountains of Khurasan between Nishapur 

 and Mashad. The famous turquoise mines of Madan are in a trappean 

 contact-rock with upper Jurassic strata. 



Proceeding to the north-east, Mr. Griesbach found the Tir-band- 

 i-Turkistan, which is the principal north-western range of the Af- 

 ghan mountains, to be mainly formed of upper cretaceous limestones, 

 resting un conformably upon the trias-jura rocks, which are found 

 locally exposed along the denuded anticlinal axes of flexure. The 

 flanking ranges exhibit massive tertiary strata, dipping steeply 

 under the recent deposits, forming the plains of Turkistan. In the 

 Kara koh region, south-east of Balkh, extensive coal-beds are found in 

 the plant-bearing series, and here the basal members are distinctly as- 

 sociated with carboniferous strata, a fact giving further confirmation of 

 the Gondwana affinities already explained. Mr. Griesbach crossed the 

 Hindu- Kush by the Chahardar pass, nearly due north of Kabul. In 

 this section, he found only the rocks already noticed, but, again, with 

 profuse intrusions of syenitic granite whereby the adjacent strata are 

 extensively metamorphosed into crystalline schists and limestones, the 



