306 Capt. Grant on the Geology of Cutcli. 



and MoUusca, whilst numerous water-fowl occupy the higher branches; the whole presenting 

 a most curious picture. That the land should gain on the sea, in these places also, is very natural, 

 as during the monsoons, when the numerous small streams convey their muddy alluvium into the 

 gulf, the roots and stems of the shrubs act as a filter, and the water passing slowly between them, 

 a great portion of the earthy matter is precipitated ; a portion also adhering to the stems. 



Effects of Floods. — Considerable damage is frequently done by the peri- 

 odical floods^ which, from the peculiar hilly structure of the country, some- 

 times rush down with a force, that carries all things before them. 



In August 1834, the rains were very violent and long-continued, and did considerable damage. 

 The river, which flows past Nurra, and through the flat, from six to eight miles broad, which ex- 

 tends from the town to the Runn, brought down so much alluvium, as to cover with a fine soil a 

 surface of 150 pragas, or nearly 1000 acres of land. This tract had been sunk by the earthquake 

 of 1819 so nearly to a level with the Runn, as to have remained unfit for cultivation. On the 

 opposite side of the province, at a village called Kundagra, not far from Mandavee, 50 pragas or 

 300 acres of soil were entirely washed away, leaving a bare sandy surface, similar to the bed of 

 a rivef ; and not far from the same spot, half a small village, with a quantity of land, was swept 

 i)odily into the sea ; 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 devastations are said 

 to have been produced. A kv/ similar inundations would alter the features of the country, con- 

 sisting of such abrupt hills and loose surface-soil. 



8. Volcanic and Trappean Rocks. 



The district coloured in the Map as composed of volcanic and trappean 

 rocks (see Map, PI. XX.) 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 compo- 

 sition 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 sub- 

 jected to violent heat since they were deposited in their present position. 

 The latter rocks, however, bear a very small proportion to the former. The 

 part coloured as volcanic shows the principal theatre of the outbursts; but 

 to mark on the Map every spot where traces of igneous action are observable, 

 it would be necessary to dot over the whole of the secondary formations. 



