46 LA TOUCHE: GEOLOGY OF WESTERN RAJPUTANA. 



decomposition of grains of felspar imbedded in the shales. Markings 

 resembling the casts of rain prints also occur on some of the lamina?. 

 The boulders are sometimes imbedded in the shales, which are then 

 contorted on a small scale. None of the boulders in the conglomerate 

 are of very large size, but some of the granite blocks reach a foot in 

 diameter. There is nothing to indicate that they may not have been 

 deposited by ordinary fluviatile action in a hollow on the lava surface. 

 The thickness of conglomerate exposed here is from 20 to 25 feet at 

 the most. At the base of Masuria hill there are about 40 feet of red 

 shales at the base of the sandstones. 



The psuedo conglomerates mentioned in Chap. IV, p. 27, are well 

 exposed along the scarp to the north-east of Sursagar and again to 

 the north of Mandor, four miles north of Jodhpur. The blocks of lava in 

 these always correspond in composition and texture with the lava of 

 the sheet immediately beneath them. Where this has a tendency to 

 weather into rounded concretions the boulders are also rounded 

 (PI. II, fig. 1), but elsewhere they are quite angular. 



From the village of Baorli, 19 miles to the west of Jodhpur, a 

 series of detached hills of Malani lavas runs in a south-west direction 

 as far as the village of Thob, 12 miles north-west of Pachpadra, a 

 distance of about 30 miles. The highest of these rise to an eleva- 

 tion of bettveen 900 and 1,000 feet above the sea, and about 300 feet 

 above the general level of the plain. Between them the ground is 

 usually at a slightly higher level than the sandy plain to the east and 

 west, and is covered in many places with a fine angular gravel, derived 

 in situ from the weathering of the lava?. The chain of hills is prob- 

 ably, therefore, composed of the highest points of a continuous ridge of 

 lavas, the lower portions of which have been smothered in sand. 



The hill at Baorli is composed of earthy looking brownish red 



rhyolite, with porphyritic crystals of pink felspar, mostly kaolinised. 



There seem to be several flows, one of which, forming the crest of a 



low ridge immediately south of the village, consists of a light green 



( 46 ) 



