DETAILED ACCOUNT OF SOME RECENT EXPERIMENTS. 85 



" trap " formation is only apparent. Basalt is not formed on the 

 sea-floor by some mysterious process of crystallisation as was 

 thought by the adepts of the school of the " Neptunists " during the 

 early part of the century, but it issues in a semi-fluid condition out 

 of volcanic vents, Lavas relatively poor in silica and rich in iron, 

 " basic " lavas in fact, like those that constitute such a large propor- 

 tion of the Deccan trap formation, flow much more easily than do 

 the more siliceous or " acid " ones. Yet their flow is not comparable 

 with that of water, and when they solidify they are still in an in- 

 clined position, however slightly so. The huge area covered by the 

 products of the eruptions whose accumulated masses probably rose 

 into high mountains, has now been levelled to the shape of a 

 plateau, and the low angles of dip of the overlapping sheets of lava 

 get lost in the irregularities produced by denudation. The forma- 

 tion is practically horizontal when considered as one mass, and has 

 only been studied as such. But there is no doubt that a more thorough 

 examination will reveal great complexity of detail notwithstanding 

 the uniformity of the general features, and it is by no means un- 

 likely that it may bring to light the existence of artesian reservoirs 

 of a very perfect character, if of limited extent. 



An experiment which seemed very promising was undertaken 



Experiment at Mhow ™ ^H at Mhow in Central India. In June 

 in Central India. jgg^ a we jj was sunk at tae engine shed of 



the Bombay, Baroda and Central India Railway. The junction of 

 the " moorrum," or decomposed basalt, and of the hard rock is 35 feet 

 below the ground surface. "Moorrum" is the name given to a 

 peculiar form of surface decomposition of the basalt : it is permeable, 

 and from it the surface wells of a large portion of the Deccan and 

 of Malwa derive their supply. In the present instance, a certain 

 amount of water issued at the junction of the "moorrum " with the 

 underlying hard rock. The well was deepened to 90 feet below 

 the surface of the ground without coming across any springs. A 

 2\ inch bore was put down at the bottom up to 13 feet, which in 



( 85 ) 



