INTRODUCTION. 3 



be seen of the strata passed through. At the same time, the total 

 absence of any traces of sedimentary rocks on the flanks of the hills 

 except in Barmer, and the frequent appearance of patches of the crys- 

 talline rocks among the sandhills, leads me to suspect that the alluvium 

 generally rests directly upon a platform of the older rocks, and that at 

 the time of the deposition of the Gondwanas and marine sediments o£ 

 Jaisalmir, the greater part of Marwar must have been dry land. 



Previous Observations, 

 In a long paper on the " Geology of India " published in the 

 1854. Journal of the Bombay Branch, Royal Asiatic 



Dr. H. J. Carter. Society, Vol. V, Dr. Carter refers 1 to the presence 

 of granite in the neighbourhood of Barmer ; to the conglomerate of 

 Barmer, 2 which he identifies with the " Greywacke or Steatitic sand- 

 stone " placed below the Transition Gneiss in the table given on 

 page 2co of the paper cited ; and to the desert sands, which he con- 

 jectures are derived from the waste of the " Punna " or Vindhyan sand- 

 stone. The lavas projecting here and there from among the sandhills 

 are considered to be the same Punna sandstones " in its concrete or 

 metamorphosed forms ;" and the quartzites of the Aravallis are also 

 referred to the same formation. 3 



In the same Journal, Vol. Vr, Dr. Carter notes the discovery by 

 1861. Dr. Impey during a journey from Rohri across the 



Dr. H. J. Carter. Jaisalmir desert to Jodhpur, of ammonites at 

 Kuchri * in Jaisalmir, referred to A. opis, Sow., a Jurassic (Cutch) 

 species ; and of fossil wood in the sandstones of Lathi, between 

 Jaisalmir and Pokaran. The " specimens of clay strata, brick 

 coloured and green, which had evidently been baked by heat, sent by 

 Dr. Impey from Jodhpur, were probably fragments of the Malani lavas 

 occurring near that place. 



1 Loc. cit. s p. 190. 



2 Ibid, p. 202. 



3 Ibid, p. 231. 



4 Loc. cit., p. 161. 



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