12 
[VOL. X. 
Records of the Geological Survey of India. 
The sandhills increase in number to the eastward; they are not arranged in long north¬ 
east—sonth-west ridges as near Umarkot, but in more irregularly formed rises, always steeply 
scarped to the north-east, and often shewing evidence of considerable denudation from 
rain. 
Three miles before reaching Naosir, some sandstone is seen, precisely like that of Balmir, 
but dipping at low angles. The same rock forms hills to the south near Sarun and Sanpha. 
The first-named ridge extends for some miles, the beds dipping about south-40°-east, 
towards an exposure of diorite, which is probably a member of the Malani beds, Porphyritic 
felsite is seen on both sides of the Sanpha hill, to the east and to the west. The relations 
of these different outcrops is not very clear; but for the occurrence of felsite west of 
Sanpha hill, it might be supposed that the broad tract from Balmir to Naosir is occupied 
by the Jurassic rocks of which the Balmir sandstones, as will hereafter be shewn, are the 
base, but the ground requires further examination. 
At Naosir a variety of felsite occurs which is very quartzose and of a reddish colour, 
almost resembling red quartzite in places. The usual dark-coloured porphyry with red 
felspar crystals is exposed at the Luni river and forms the range of hills south of Jasol- 
The large hills to the south-east in the direction of Jailor are probably of the same rock, 
which may extend as far as the Arvali range. 
North of the Luni river near Jasol, a somewhat depressed plain, in the neighbourhood 
of the town of Panchbkadra, has long been the seat of an extensive manufacture of salt. 
The tract is much covered with sand, but is lower than the surrounding country, and may 
be the site of an ancient salt lake, or of a tract of low country covered at one time by the sea, 
if an inlet extended up the Luni valley. The salt is obtained from pits into which brine 
trickles, and is evaporated by the heat of the sun. 
Por many miles below Jasol no rock is seen in the bed of the Luni river, and there is a 
flat alluvial plain south of the river, which here runs east and west. At Jasol some coarse 
conglomerate, found on the bank of the stream and used for building, is apparently a sub- 
recent formation. From Jasol to Jodhpur, a distance of 60 miles, the whole country appears 
to be alluvial; no rock is met with, except in a few isolated hills, all of which consist of the 
Malani l'elsites. 
These felsite-porphyries and their associates, here varying more than usual in character, 
and comprising beds which unmistakably resemble volcanic ash, are well developed at 
Jodhpur, and the greater portion of the town itself is built upon them. The commonest 
variety is a brownish-red porphyry with the usual red felspar crystals, the ash beds being 
well seen about three miles south-west of the town. 
Jodhpur sandstones.—The long ranges of low flat-topped bills, however, which extend 
for many miles south-west, west, and north of Jodhpur, consist of red sandstone, which may 
perhaps be of Vindbyan age. It is certainly quite distinct from the sandstones of Balmir, 
and appears to be older. It is, as a rule, rather coarse, often obliquely laminated, and it 
frequently contains small pebbles. It is largely used as a building stone ; some kinds bear 
carving, and its resistance to the destructive effects of exposure is amply proved by various 
old buildings in the neighbourhood of Jodhpur. 
The Malani felsites only occupy the town itself and a patch of ground extending three or 
four miles to the south-west and north-cast, the sandstones resting upon them to the north-west, 
and a sandstone outlier forming the fort of Jodhpfir itself. The sandstones are quite 
unconformable to the felsites. To the east and south-east of the town is a broad sandy 
