VI. 



ON THE 



GEOLOGICAL AND MINERALOGICAL 

 STRUCTURE 



OF THE 



Hills of Sitdbaldi, Nagpur, and its immediate vicinity. 



By the late H. W. VOYSEY, Esq. 



Assistant Surgeon His Majesty's 67 th Foot. 



HE hill of SildbalcU although agreeing in form and interior structure 

 ith other basaltic hills in its neighbourhood, merits a more particular 

 description on account of some peculiarities in the composition of the 

 ain rock, hitherto unnoticed by Geologists, and for the opportunities 

 fforded by its extensive quarries of studying the varied structure of the 

 ocks of the trap family, which is rarely to be seen in so distinct a manner. 



The mass of the hill is composed of porous basalt, with a semi-column- 

 r appearance, derived from numerous vertical fissures. It passes in some 

 laces, both in a gradual and abrupt manner into a coarse porous wacken 

 or indurated clay, which in its turn changes in a similar manner to the 

 nodular basalt or wacken, of which the northern and southern summits 



of 



