STRATIGRAPHICAL FEATURES, I 7 



order of succession of the strata. So far as I am able to express an 

 opinion, judging from the published descriptions, they appear to 

 belong to the Delhi system as restricted in the second edition of the 

 Manual. 1 They consist of dark grey micaceous schists, or schistose . 

 slates, with thick lenticular beds of white or bluish white quartzite, 

 the latter often forming hills of considerable size, in which the quartz- 

 ite is the only rock visible. The strike of the whole series is from 

 north-east or north-north-east to south-west or south-south-west, 

 parallel to the main range of the Aravallis, and they are always very 

 highly inclined or vertical. Along the foot of the Aravalli range, in 

 the district of Godwar, these rocks contain bands of calcareoue 

 schist which, when in contact with intrusive granite, has become 

 altered into a white crystalline marble. A large mass of this occurs 

 at the village of Sarangwa, about four miles west of Desuri, and is 

 largely quarried for building purposes. The marble rests upon a 

 large dome-shaped boss of granite, a portion of the large spread of that 

 rock which occupies the ground between the base of the hills and 

 Erinpura. A lenticular fissure containing large rhombohedral crystals 

 of calcite or Iceland spar was recently discovered among the calca- 

 reous schists in the hills about seven miles south-east of Sadri, near 

 Desuri in Godwar. Some of the crystals are fairly transparent, but none 

 are without flaws, and the bulk of them are too opaque to be of any 

 value. 



The famous marble quarries of Makrana are situated in exactly 

 the same position as regards the range, but are about 140 miles to the 

 north-west of Sarangwa. Here the marble forms bands very con- 

 stant in width, in micaceous and calcareous schists with a north- 

 north-east — south-south-west strike and very high easterly dip. The 

 rocks form a series of low ridges parallel to each other, separated 

 by level stretches of blown sand. There may be only one band of 

 marble repeated by folding. The bands of marble alone are worked 



1 Manual, Geology of India, 2nd edition, p. 68. 



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