1840.3 



On the Geology of Cutch 



833 



appearance of a newly-laid macadamised road. Their interior, how- 

 ever, has a much more solid coBstruction, as is well seen in numerous 

 deep clefts and ravines with which the hills are in all directions inter- 

 sected. 



One of thep.e ravines, near the village of Doonee, is 50 or 60 yards 

 broad, and nearly 100 feet (Jeep ; and its perpendicular sides are composed 

 of CI mpact columnar basalt of a greenish grey colour ; the columns being 

 perfect polygons, and of a very large size. This rent must have been 

 formed by some convulsion, as it reaches nearly to the summit of the hill ; 

 and the only water that could ever have flowed down it being that which 

 falls t li its sides and bed, and must be very little. 



Alternntinm of Basalt with Strata of the Upper Secondary Formation. 

 — Near Kurra, on the borders of the Runn, a hill called Joge-ki-bit, 

 basalt alternates with slate-clay, limestone slate, slaty limestone, 

 and a lauiinated loam. The strata dip from 40° to 50" to the north, 

 which being at a higher angle than that at which the bill itself rises, it 

 causes them to crop out ; the surface being also broken into several 

 distinct ridges. The igneous rock alternates three times. In one in- 

 stance it underlies a stratum of hard slate- clay ; in another it occurs 

 between a coarse, soft sandstone, and slate-clay, and sandstone slate ; 

 and it also forms the conical summit of the hill, which is not more than 

 ten feet in diameter. The basalt desquamates in flakes, but has a 

 centre of compact rock. The same inclination of the beds is continued 

 through the hill. 



Alternations of the Calcareous Grit with Basalt. — At the village of 

 Doonee, above mentioned, the banks of the river present a perfectly 

 perpendicular wall, from 15 to 20 feet high, and are composed of the 

 calcareous grit, or coarse limestone alternating with basalt, in the fol- 

 lowing order : first, grit ; then a horizontal bed of rounded pieces of ba- 

 salt ; and next, another stratum of the grit, 15 feet in thickness; the 

 "whole being covered by the basalt forming the hills. 



Another good example of this alternation is near the village of Keroee, 

 at the eastern limit of the formation. The btmks of a river are here com- 

 posed, in some places, of the basalt forming the Doura range ; and ia 

 others, entirely of the limestone grit, which in one place overlies the ba- 

 salt, but forced up into anticlinal lines, as if the igneous rock had been 

 protruded from below ; the broken state of the strata showing that it 

 was not originally deposited in this position. The bed of the river at 

 this place is entirely composed of basaltic columns ; their horizontal 

 sections forming a regular pavement j and large masses of the columns. 



