COEALLIEEROTTS SEEIES OE BIND. 



193 



Explanatory Sections. — In the Laki range, south-west of Amri 

 on the Indus, arc dark-coloured hills which contrast with the cliffs 

 of grey and white jNiiminulitic limestone behind them. A section 

 close to the hill called Barrah is given by "W. T. Blanford, F.E.S. ; 

 and it shows that the range consists of three parallel ridges (see fig. 1, 

 p. 194). 



The outer, to the east, is composed of Tertiary rocks, while the 

 intermediate one consists of Cretaceous beds faulted to the eastward 

 against the Lower Eocene strata, and clipping under them to the 

 westward. 



This section shows the normal sequence of the groups of strata 

 from the Cretaceous to the Khirthar inclusive. Above the Isummu- 

 litic limestone of this last group the I^ari and Gaj series are wanting, 

 and the Ivlanchhar succeeds*. 



On the Gaj river, in the Ehirthar range, W. T. Blanford remarks 

 that a thickness of at least 25,000 feet of strata is exposed (see 

 fig. 2, p. 194). The succession from west to east is : — unfossiliferous 

 strata, probably of Cretaceous age, followed by Khirthar strata (the 

 Eanikot series, the lowest Eocene, being absent) ; then the lower 

 and upper JSTari series come in, and are followed by the Gaj and 

 the Manchhar deposits. 



The lowest coralliferous deposits occur in the soft olive shales and 

 sandstones with volcanic ash, belonging to the Cardita Beaumonti 

 series below the trap. The accompanying remains are those of 

 Amphiccelian Crocodilia and Echinodermata ; and the deposit was 

 neither a reef-structure nor a deep-water one. 



The lower part of the Eanikot series, resting immediately on the 

 trap, consists of soft sandstones, shales, clays with gypsum and lignite, 

 and pyritous shale. A few fragments of bones and some dicoty- 

 ledonous leaves occur. These freshwater strata are succeeded by 

 highly fossiliferous marine limestones, often brown in colour, inter- 

 stratified with sandstones, shales, clays, and ferruginous bands. 



Kummulites appear for the first time, and there is a grand develop- 

 ment of Corals, Echinodermata, Gasteropoda, and Cephalopoda. It 

 was not a very deep-water formation. Erosion of the surface of the 

 Eanikot strata occurred before the deposition of the next series. 



The Khirthar series inclnd.es in its highest portion a massive, pale 

 or dark grey, hard, compact jSTummulitic limestone whose extreme 

 thickness is 3000 feet. It thins out to the south-west, and disap- 

 pears within a distance of twenty-five miles of its greatest develop- 

 ment. Other ISFummulitic limestone -beds are found, which may be 

 lower in the series ; and they and the main group are represented 

 elsewhere by shaly limestones and sandstones with calcareous bands. 

 In some districts flint occurs in a limestone with Alveolince. The 

 lower members of the series are often wanting, and are well repre- 

 sented by shales, marls, and sandstones and where these are present ; 

 unconformity with the underlying .Eanikot beds is not seen ; but 

 where they are absent the j^ummulitic limestone (as in the Laki 

 range) rests unconformably. The compact limestone is of course 

 -* Memoirs Geol. Survey of India, vol. xvii, pt. 1, p. 131. 



