332 



On the Geology f>f Cutch 



[Oct. 



somewhat similar to a very porous cinder, are found adhering to the 

 marl, and in the rubble of the bank. 



Large blocks of the shelly limestone, composing the summit of the 

 hill, are scattered about its sides and base ; and some of them, mv guide 

 informed me, fell during the earthquake of 1819; and the abrupt and 

 steep sides are, no doubt, due to the action of water. Numerous fossils 

 are found lying about, characteristic of the nuinmulitic limestone. 



1 have minutely described this hill, in the hopes of impressing others 

 "with the same belief as myself, of the cause of its elevation. 



Near the village of Nambye, in the Charwar range, a basaltic dyke 

 traverses beds of thinly laminated slate-clay and layers of limestone slat ». 

 Jn the immediate vicinity of the dyke the s'.rata dip in all directions, and 

 form even anticlinal line:;. The basalt is very hard, compact, and of a 

 dark blue colour, and presents irregular masses, without the slightest ap- 

 proach to a columnar structure. 



DhfJnct Periods of Volcnmc Eruption. — That the volcanic eruptions 

 have occurred at many distinct periods, is also evident, from the different 

 formations with which the igneous roc1;s are associated, and from 

 the variations in their characters. Thus, in the same section, 

 the lower part frequently consists of large, rolled, or water-wora 

 masses, whilst the upper portion is columnar : in other places 

 the basalt -.ilternates with a calcareous grit or coarse limestone, 

 having a tabular structure, but always distinctly stratified, and very 

 brittle, so as to present perpendicular banks. This limestone is ge- 

 nerally associated with basalt, where the latter is raised into hills : aud 

 from the fact of cmgular pieces of basalt or igneous matter being iaibed- 

 ded in it, would incline one to believe that, in such cases, it must be 

 contemporaneous, though it often regularly alternates with it. In other 

 places the basalt is interstratified with a pure crystalline limestone or 

 travertin. 



The principal mass of igneous rocks lies towards the southern depart- 

 ment of the province, and forms a group of hills called t!ie Doura rannje ; 

 the intervenin.g spaces and the ground at their sout= era base generally 

 assuming a porphyritic structure. The northern parts of the range have, 

 for the greater part, a fiat, smooth outline ; but in the interior of tJie 

 group are many clusters of small, conical liills, arranged round a circular 

 space, inclosing a kind of hollow. The sides of these cones are very- 

 steep, and invariably present innumerable horizontal lines, forming rings 

 reseuibliiig narrow paths. The surface being covered with basalt, ia 

 very small pieces, is totally devoid of vegetation, and has precisely the 



