1840.] 



On the Geology of Cutch. 



315 



sionally of a large size. One specimen, wliich was flattened, was four 

 inches in breadth, and the outer surface was carbonised, but the interior 

 was filled with sand : this was generally the case, though other speci- 

 mens were carbonised throughout, and some were mere impressions. 

 In digging wells within the limits in which they occur, coal was frequent- 

 ly found, but always in thin beds ,* and some of it ought more properly 

 to be called lignite. 



Extent of Coal-field. — The coal-field, if it may so be termed, is 

 bounded to the north by the upper secondary or laminated slate-clay 

 and limestone slate formation ; and to the south it is cut off abruptly 

 by a low range of volcanic and trap hills. I could not ascertain whether 

 it had ever been covered by any conformable, stratified deposits. Thia 

 beds of coal have been found in various other parts of the formation. 

 The general structure of this series of strata, the quality of some of the 

 coal, the nature of the sandstone and slate clay, the impressions and re- 

 mains of reeds, ferns, &c., the bands of ironstone, the dislocations by 

 dykes, slips, &c., all bear an analogy to the coal-fields of England ; but 

 I am inclined, from the vegetable remains, to consider this deposit an 

 equivalent of the oolitic coal of England, and not of the regular carboni«' 

 ferous system. 



Alum "Works near Mhuur. 



The ground on which Mhurr is built, consists of high, irregular banks 

 of marl of every variety of colour, but in a most confused and shattered 

 state. It is surrounded on three sides by steep hills, forming a kind of 

 amphitheatre ; and nothing can be more desolate than its appearance. 

 North of the town is a high table-land, which extends to some hills about 

 one mile and a half distant. It is composed, near their base, of a ferru- 

 ginous quartzose sandstone, on which the variegated marls rest ; the lat- 

 ter being covered, in many places, with a bed of coarse gravelly detritus, 

 six or eight feet thick. Imbedded in this gravel, are some very large 

 masses of basalt, and of a very hard, black stone, composed of grains of 

 quartz cemented by an almost black oxide. They are cut into mill-stones 

 for grinding flour. The whole are evidently boulders from the hills to 

 the northward, which were mentioned in the first part of this memoir, as 

 consisting of quartz and basalt. This plain terminates, to the south" 

 ward, in a high bank overlooking the town, and intersected in one part 

 by a large dyke of spheroidal basalt, which has apparently so indurated 

 the strata of variegated marl in its vicinity, as to permit them to be 



