46 Carter on tlie Persian Gulf. [No. 1. 



capped by 20 to 30 feet of a calcareous, shelly grit more or less coarse, 

 more or less chalky in consistence, and in which the shells are semi- 

 fossilized or semi-lapidified. Whether these two distinct deposits 

 are conformable to each other or not I am ignorant, bnt the sketches 

 of them which I possess are in favour of the former; at the same 

 time, although conformable, they may contain fossils of different 

 geological epochs, which would prevent their being grouped toge- 

 ther. Unquestionably the calcareous shelly grit of Kishm is iden- 

 tical with the same formation, slightly modified, in the other parts 

 of the Gulf, and which modification identifies it with the same 

 deposit on the south-east coast of Arabia and that on the outer or 

 western coast of Khattywar in India, which I have termed 

 " Milliolite," and assigned provisionally to the Miocene era. Pro- 

 visionally, therefore, it might be as well to consider that of the 

 Persian Gulf together with the clay, also Miocene. 



Another interesting point then presents itself, viz. — "When were 

 the volcanic islands of the Gulf raised above the sea ? And this 

 seems to be answered by the position of the Miocene formation at 

 the island of Kishm, which, resting upon these rocks, and being 

 capped with a material which must have been deposited at the 

 bottom of the sea, proves that the elevation of these islands, or this 

 volcanic out-burst, took place after the Miocene period, and was 

 the last great convulsive displacement to which the earth, under 

 and about the Persian Gulf, has been exposed ; for there has not 

 been any other subsequent sedimentary deposit of any consequence 

 raised above, or probably deposited in, the sea of the Persian Gulf 

 since that period. 



Having arrived so far then, we may with profit, perhaps, trace this 

 volcanic agency a little further, and first following the Mekran coast 

 on to Kurrachee, we find an extensive area in the province of Luss, 

 where this disturbance is still iu great activity ; not, however, pour- 

 ing forth fire and lava, but sulphurous gas and water, which, bub- 

 bling through a clay deposit of great thickness, has thus formed 

 mud-mountains and mud-craters over an area between the highland 

 of the interior and the sea which occupies the greater part of this 

 province. Moreover, the very same kind of sedimentary formation, 

 equally broken up too as that on the island of Kishm, characterizes 



