oi4 JOURNAL, BOMBAY NATCRAL HIST. SOCIETY, J'ol. XXVIl. 



hystricula but with light green spikes, frequents like the latter, bare grave 

 patches round Jaisalmer and elsewhere. Further away from the town, th 

 plain becomes more sandy (Plate XXXIII- A., on which the Fort may stiU b^ 

 distinguished in the distance, and XXXIII-B.). 



The fiat, gravelly plain near Devikot had in many places been inundated, an d 

 here grasses, sedges and species of Ammannia grew luxuriantly. Especially was 

 this the case about three miles north of the village, where a shallow, artificial lake 

 had been constructed, now almost dry. Mimosa hamata is very common round 

 such places. The gravel vegetation close to the village was well developed. We 

 noted Heliotropium undulatum and Sericostoma pauciflora (Plate XXXIV- A.), 

 Boerhaavia diffusa, Tribulus terrestris and T. alatus, Seetzenia orientalis (Plate 

 IV-A.) The order Ficoidece was unusually well represented. Round Vinjorai, 

 Blepharis sindica and Capparis decidua are common on gravel. S W of Seu 

 village the gravel grass flora is particularly well developed. Eleusine sp., 

 Aristida sp. and Chloris pallida, all low grasses, grow here in large patches, the 

 last mentioned conspicuous because of its whitish, withered spikes. Striga 

 euphrasioides abounds here, especially, on moist ground. Along the path 

 towards Kotda, the gravel vegetation becomes more shrubby, and consists 

 chiefly of Salvadora, Capparis, Acacia Senegal, Lycium, Zizyphus and Calotropis. 

 Nearer Kotda hill sandy soil predominates. 



liock Formation. 



Apart from isolated hills and rocky ridges of no great extent, the following 

 three larger rocky areas were visited by us : — 



A. The Kailana-Jodhpur-Mandor plateau. 



Resting unconformably on the older Malani lavas, there is here an extensive 

 sandstone plateau, rising abruptly from the plain and reaching perhaps 200 feet 

 in height. Jodhpur city is situated close to the southern edge of this plateau 

 (see Plate III- A.), and the Jodhpur-Phalodi railway line foUows its eastern 

 margin. Near Kailana, there are some detached outliers. No indubitable 

 organic remains are known from this plateau, but other evidence points to its 

 Vindhyan origin. In all probability the thickness of the deposits must previ- 

 ously have been considerable, and what is left is subject to severe denudation. 

 The rock generally consists of a rather fine, gritty, reddish material, and is an 

 excellent building stone ; at the same time it is well suitable for carving, as parts 

 of the imposing Jodhpur Fort testify. Round Mandor the surface of the plateau 

 is often cracked into large rectangular slabs, particularly noticeable in the rocky 

 depressions (Plate XXVII-A.). 



B. Jaisalmer plateau and outliers. 



The town of Jaisalmer is built on an outlier of this plateau, the fort occupyiig 

 its highest part (see Plate III-B.). The strata, which are highly fossiliferous, 

 are well exposed in many places close to the town. We give the following sections 

 (thickness of strata approximate) : — 



(a) Section of the hill with corner-tower of town-wall, east of guest-house. 



1. About 60 feet of yellowish brown sandstone, rather brittle, with 

 large marine shells and (near top) small sea-urchins ; 



2. About 35 feet of greyish, harder sandstone, apparently without fossils. 

 (6) Section of scarp north-east of guest-house : 



1. About 5 feet of very hard, fine-grained dark brown limestone without 

 fossils, subdivided into several layers by means of thin, interstrati- 

 fied, gritty sheets. 



2. About I feet of very hard, dark purplish limestone containing masses 

 of shell-fragments. 



' 3. About 15 feet of soft, gritty, yellowish brown sandstone, with num- 

 bers of marine shells, excellently preserved. 

 4. Limestone. 



