2 THE TERTIARY FOSSIL ECHINOIDEA 



West and north-west of Cutch a wide area is occupied by the Indus delta, and the 

 Tertiary beds only reappear in Sind after an interval of about 80 miles. There is nearly 

 the same break to the southward before the corresponding formations are met with in 

 Kattywar. The Sind beds form a part of the widely developed Tertiary region that 

 extends northward to the foot of the Himalayas, and westward to the Persian Gulf or 

 even further. The classification of the Sind Tertiary beds has already been explained*, 

 and the different subdivisions may now be accepted, on the evidence of the corals and 

 Echinoidea, as occupying the following position in the geological series : — 



Manchhar or Siwalik, Upper .... Pliocene. 



„ „ Lower .... Upper Miocene. 



Gaj Miocene. 



Nari, Upper Lower Miocene, 



„ Lower Oligocene. 



Khirthar Eocene. 



Ranikot Lower Eocene. 



The beds beneath the Ranikdt group form apparently a passage .to the Cretaceous 

 system . 



Of these diiferent groups the Lower Nari and the Gaj, both highly fossiliferous 

 marine formations, occur with but little change throughout Sind ; both, however, dis- 

 appear completely further north. The Ranikot appears to be purely local, and is 

 confined to the country near Tatta, Jhirak, and Kotri. The Khirthar group comprises 

 the massive Nummulitic limestone of the Baluchistan frontier, in places 1500 to 3000 

 feet thick, and a great thickness of shales, marls, and sandstones beneath the limestone. 

 Some of these shales and marls on the frontier of Northern Sind and to the westward 

 may represent the Ranikot group of the Lower Indus valley, although they do not 

 contain its peculiar fauna. Where the Khirthar beds rest upon thfe Ranikot group 

 they have lost greatly in thickness, the great limestone bed is represented by a number 

 of thinner beds interstratified with sandy and shaly deposits, and the fauna, although 

 rich, differs materially from -that of the great limestone band of Northern Sind. 

 Further research to the northward has shown, in fact, that these great belts of Nummu- 

 litic limestone are of very irregular occurrence, that they vary in thickness by thousands 

 of feet in the course of a feAv miles, and that they may occur at different horizons in the 

 Eocene system. 



The Tertiary rocks of Kachh were divided by Captain Grantf, the first geological 

 explorer of the province, into Nummulitic and Tertiary, the former, in accordance with 

 the views prevalent at the time, being considered Pre-Tertiary. MM. d'Archiac and 

 Haime, however, classed both divisions as Eocene; and their views, which were quite 

 erroneous, have long misled geologists both in India and Europe. Mr. Wynne, in his 



* " Fossil Corals of Sind," Pal. Ind. ser. xiv. vol. i. 1880. 

 t Trans. Geol. Soc. ser. ii. vol. v. pp. 300, &c. 



