86 VREDENBURG : RECENT ARTESIAN EXPERIMENTS IN INDIA, 



g5 hours filled the well up to 41 feet 6 inches from the surface of 

 the ground. The diameter of the well was 25 feet, and the spring 

 had delivered 49,459 gallons. 



The locality does not seem to be in a very favourable situation, 

 for it is only a short way north of the scarped face of the Vin- 

 dhyan range. 1 Thus the surface of the ground at the locality 

 where the well was sunk is at a higher level than the neighbouring 

 region at a short distance further south, and it could not be expected 

 under such conditions that the well would overflow. The following 

 views were expressed by Mr. Medlicott on the subject of this experi- 

 ment : "It would seem impossible for a sufficient head of water to 

 accumulate for a surface delivery at Mhow- On the other hand, 

 trappean rocks are very retentive of water and thus favourable for 

 constancy of supply. The streams in such a country carry water 

 much later than in similar ground formed of other rocks. This con- 

 sideration would be in favour of a supply by deep wells, of which the 

 engine shed well gives a very promising example." It is to be 

 regretted that this experiment has remained an isolated one so far 

 as is known. 



Besides the possible existence of reservoirs formed by loose tex- 

 tured tuffs and intertrappean sandstones, or by fissures and caverns 

 in the basalt itself, it must be kept in mind that the products of the 

 eruptions have overwhelmed a very irregular ancient land surface. 



Irregularity of the floor In man y P laces the decomposed rock surfaces 

 underling the formation. corri p OS j n g t hi s old land area and the ancient soil 



must form a more or less porous layer at the base of the volcanic 

 formation, and, if the shape of this underlying surface could be 

 known, it would be possible to select some likely places for experi- 

 mental borings, as the porous layer might be locally disposed in such 



' The name " Vindhyan " has been applied by the Geological Survey to a peculiar group of 

 strata which have already been spoken of ; but in a geographical sense the name applies to the 

 rectilinear scarp north of the valleys of the Nerbudda and Son, the eastern part of which consists 

 of " Vindhyan sandstones," but which, further west, is composed only of volcanic rocks. 



( 36 ) 



