DETAILED DESCRIPTIONS OF ROCKS. 45 



been gradually buried by the sandstones, which are quite horizontal, 

 There is no conglomerate at the junction. 



2. Quarter Sheet 20 N. E. 



Along the northern margin of this quarter sheet the Vindhyan 

 sandstones form several plateaus of considerable extent, the largest of 

 which stretches for several miles to the north and west of Jodhpur. To 

 the west they are found as far as the neighbourhood of Shergarh, 

 where they gradually disappear beneath the sand. At Balasar, 

 1 1 miles north-east of Shergarh, the sandstones rest horizontally upon 

 a very uneven surface of the Malanis, and the junction can be traced 

 along the scarps to the north and south of the village. Here also 

 there is no conglomerate at the base of the sandstones. The junction 

 is also exposed along the scarps to the north of Chaunda, 16 miles 

 north-west of Jodhpur, and is of a similar character. 



The former extension of the sandstone plateau over the whole area 

 is well shown by the number of detached conical flat topped knolls 

 scattered over the plain. Several good examples of these " witnesses " 

 [Zeugen) may be seen near the village of Ghoriala, a few miles east of 

 Balasar (PI. II, fig. 2). 



At Jodhpur the Malani lavas form a large flattened dome-shaped 

 mass extending for about five or six miles to the west of the city and 

 surrounded by scarps of the Vindhyan sandstones. Patches of true 

 conglomerate containing rolled pebbles and boulders of granite and 

 other crystalline rocks, are exposed at the base of the sandstone in a 

 shallow valley west of Chopasni, about five miles west of Jodhpur, at the 

 base of Masuria hill about a mile south-west of the city, and at the base 

 of a scarped outlier about half a mile to the south-west of the old Resi- 

 dency at Sursagar. Here it is associated with some finely laminated 

 purple shales, containing globular patches of a white substance resem- 

 bling kaolin, which give a peculiar mottled appearance to the surface 

 of the laminae. This substance is apparently derived from the 



( 45 ) 



