Capt. Grant on the Geology of Cutch. 307 



Evidence of the disturbing power of Igneous Agents. — It is impossible to 

 desire clearer evidence of the disturbing power of igneous agents than is de- 

 veloped in Cutch. The shattered appearance of the country in some places, 

 the upraised hills in others, with the igneous rock or moving agent, either di- 

 rectly under them, or immediately in front of the outcrop of their strata; the 

 angles to which the beds have been raised varying from a gentle, unfractured 

 slope to the most complete dislocations; the vast variety in the composition of 

 the igneous matter, from the most loose and clay-like form to the most com- 

 pact and perfect columnar basalt; the crater-like shape and construction of 

 some of the hills, from which large lava or basaltic streams can be traced, 

 prove the igneous origin of these rocks, and the vast effects which they 

 have produced on the general appearance of the country. Moreover, it is 

 not necessary that the igneous matter should be on every occasion apparent ; 

 as, where we find a large mass of basalt which has evidently come from 

 below, lying on a plain, behind a hill presenting a bluff cliff towards the 

 igneous rocks, and the strata sloping sharply from them, the conclusion is 

 obvious, that the hill must have been raised by the outburst of the volcanic 

 matter; and it is equally just to infer, that, in its passage from below, it must 

 have disturbed, more or less, the various beds through which it passed ; and, 

 therefore, that the form of many hills may be owing to a latent exercise of this 

 power, even where no traces of the igneous matter are visible near the sur- 

 face, or near the raised strata. That the greater number of these igneous 

 rocks have been forced up, and are not portions of lava streams which have 

 flowed from volcanos, is very evident, from the manner in which the super- 

 imposed strata are affected by them. 



In a preceding part of the paper I have described a hill of quartz rock near 

 Mhurr, and shown that its strata have been violently disturbed ; and 1 have 

 also inferred, from the nature of the rock, that its characters are due to grains 

 of sand having been agglutinated by volcanic heat. In detailing the phaeno- 

 mena presented by the second formation, I have shown that its strata have 

 been also subject to great dislocations. 



The following wood-cut presents an example of a large dyke of basalt 

 which has cut through the strata in the river near Jaumtra, and thrown them 

 off in opposite directions. 



VOL. V. — SECOND SERIES. 



