328 



On the Geology of Catch, 



[Oct. 



sardv swface, similar to the bed of a river ; and not far from the same 

 spot, Iia'if a small village, with a quantity of land, was swept bodily into 

 the s?.a ; large trees being uprooted and carried down by the flood. At 

 Pheraudee, 12 miles N. E. from Mandavee, at Mandavee, and many other 

 places, great devastntions are said to have been produced. A few simi- 

 lar inundations Vv'ould alter the features of the country, consisting of such 

 abrupt hills and loose surface-soil. 



8, Volcanic and Trappean Rocks. 



The district composed of volcanic and trappean rocks is one of the 

 principal features in the geology of Cutch, not only from the space it 

 occupies, but from the phaenomena which it presents. 



The igneous origin of trap being acknowledged, I shall always speak 

 of it and lava under the comprehensive term of igneous rocks, as in com- 

 position they differ only in the proportions of hornblende, felspar, and 

 augite, and as they all appear to have originated in the same cause, and 

 to have equally disturbed or affected the neighbouring strata. But there 

 appears to be a very marked distinction between those rocks which have 

 been in fusion below the surface, and subsequently forced up, and those 

 sedimentary formations, which have an altered appearance, and have been 

 evidently subjected to violent heat since they were deposited in their 

 present position. The latter rocks, however, bear a very small propor- 

 tion to the former. 



Evidence of the disturhhg power of Igneous Agents.— \t is impossible 

 to desire clearer evidence of the disturbing power of igneous agents than 

 is developed in Cutch. The shattered appearance of the country in 

 some places, the upraised hills in others, with the igneous rock or moving 

 agent, either directly 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 compact and perfect columnar ba- 

 salt ; 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, 



