1845.] Notes on the South Mahratta Country, fyc. 303 



in the state of dykes in the sandstone and limestone, has converted the 

 former into quartz rock, and the shales of the latter into jasper and 

 chert, indicating a posterior or contemporaneous origin. 



The disturbance and metamorphic effects produced by the eruption 

 of this granite do not appear to extend to any great distance from the 

 foci of plutonic disturbance. The sandstone ranges in the S. Mahratta 

 country are usually little inclined, particularly in the ranges S. of the 

 Malpurba, resting unconformably on the hypogene schists and granite, in 

 highly inclined stratification ; but travelling a short distance north we 

 find them showing more signs of plutonic disturbance, and, according 

 to Christie, the sandstone of Chick Nurgoond is uplifted at an angle of 

 40° resting on the vertical hypogene schists ; a fact indicating two eras 

 of plutonic disturbance. 



It is a striking fact that no fragments of undoubted granite or gneiss 

 have been noticed in the pebbles of these, sandstone conglomerates, 

 which consist chiefly of quartz, chert, jasper, basalt, flinty slate, and 

 the hard portions of the chloritic and actynolitic schists, the two last 

 rocks bearing a small per centage in relation to the rest, and those of 

 quartz greatly predominating in the lower beds. The inference is, 

 either that the attrition which converted the wreck of the pre-existing 

 rocks into sand and gravel was so great, as to grind down their mass 

 beyond the possibility of recognition, leaving nothing but fragments of 

 their hardest nodules and veins, or that the oldest granite was still un- 

 denuded, and with the gneiss at this era was as yet but partially uplift- 

 ed and retained its natural subordinate position. 



It is certain however from the included pebbles of the flinty slate, 

 jasper, actynolited and chloritic schists, that the plutonic action of 

 granite had commenced prior to the origin of the sandstone, and had 

 metamorphosed or crystallized the hypogene, or rather formed schists of 

 the wreck of which the sandstone is formed. 



If this reasoning be admitted, it is obvious that at least two epochs 

 of great plutonic activity have taken place. The first anterior to the 

 formation of the limestone and sandstone, by which the hypogene schists 

 were rendered crystalline and partially subverted. The second, pos- 

 terior ; and marked by another granitic eruption, which burst up 

 through fissures in the old granite, altering the limestone and sand- 



2u 



