•INTRODUCTION. 



7. Nummulitic limestone .... Tertiary 



6. Ammonitiferous beds of Kuchri . 



5. Jaisalmir limestones and sandstones 



4. Barmir sandstones . . • 



3. Jodhpur sandstones . . . 



2. Shales and boulder bed of Lowo and Pokran ? 



I. Ma'ani felsite, porphyries, syenite, etc 



•} 



Jurassic. 



? Vindhyan. 



Each of these formations is described in detail. The name of 

 Malani, from the district of Marwar in which they were first met 

 with, is given to the volcanic series of porphyritic lavas and ash beds, 

 which have since been found to be the most widespread rocks in 

 Jodhpur territory. The occurrence of fragmentary plant remains in 

 the Barmer sandstones is noted, and these rocks are correlated with 

 similar sandstones containing fragments of silicified wood occurring 

 beneath the marine Jurassic beds of Jaisalmir. A listrof fossils from 

 the latter beds is also given. 



In the second paper Mr. Blanford gives an account of the phy- 

 sical characteristics of the desert, with especial reference to the sand- 

 hills, which he shows are entirely due to the movement of the sands 

 driven before the prevailing south-west winds, and discusses the 

 probabilities of a former extension of the sea over a part of this area, 

 in order to account for the production of the sand. 



Of the papers communicated by Mr. Hacket to the Records of 

 l88o . the Geological Survey there are three which 



c. A. Hacket. deal to some extent with the geology of the area 

 now described, or its economic resources. The first of these, pub- 

 lished in 1880, 1 is a discussion of the mode of occurrence and origin 

 of the salt which is the characteristic product of Western Rajputana. 

 Mr. Hacket thinks that the accumulation of the salt may be accounted 

 for by the present operation of drainage and evaporation, but finds 

 a difficulty in attributing to these causes its local concentration in such 

 places as the Sambhar Lake, and seems inclined to account for such 



1 Rec. Geol. Surv. Ind., Vol. XIII, Pt. 3, p. 197. 



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