SKETCH OF THE 



greenstone. The latter, in many situations, perfectly resembles the green- 

 stones of the overlying trap formation, and frequently contains imbedded 

 calcareous spar, as do also the greenstone schists. The greenstones, and 

 less frequently so, the greenstone schists exhibit a porphyritic structure. 

 The low hills of the valley of Uclayapur consist of a series of alterna- 

 tions of argillaceous schist and greenstone, greenstone schist, &c. — and 

 the greenstones occur both stratified and in regular prismatic beds, alter- 

 nating with other strata. There is another rock which frequently occu- 

 pies the place of the greenstones in alternations of this last mentioned 

 rock with argillaceous schist, the relative position to the argillaceous 

 schists being similar. It appears to he greenstone, which has lost its horn- 

 hlende, and is principally composed of felspar of a greenish grey color, 

 associated with a proportion of quartz, greater or less in different si- 

 tuations. A similar occurrence is described as taking place in Wales 

 — this rock exhibits a porphyritic structure, and somewhat resembles 

 the clay stony porphyry of Jameson. It is found abundantly in the 

 valley. 



Several of the argillaceous schists, especially those which pass into 

 greenstone and greywacke schist, as well as the greenstone schists them- 

 selves, are capable of being cut into long masses of various thickness and 

 breadth, — and also into flat slabs. Some of these masses are fourteen 

 feet in length, and are used in place of beams to support the flat roofs 

 of the numerous rectangular buildings of Hindu origin, which abound 

 in this portion of India. The flat slabs are used as roofing stones, and 

 the series of pillars on which these flat-roofed buildings are supported, 

 are also solid masses of the same rocks. These are often fancifully carved. 

 Indeed, these stones are used in place of beams in all the buildings, 

 whether flat-roofed or domed, in this part of the country, excepting in 

 such as are built of marble. 



