DETAILED ACCOUNT OF SOME RECENT EXPERIMENTS. 75 



the river-bed might be enclosed by impervious strata in such a 

 manner as to derive its supply from an area situated at no great 

 distance from the river, but where the surface of the ground-water 

 stands at a somewhat greater altitude than in the immediate neigh- 

 bourhood of the river. It is probable that a similar phenomenon 

 might take place in many river-beds; but in such a position the 

 supply is usually not of much use. Of a similar nature is the occur- 

 rence mentioned by Mr. Medlicott as having taken place in the year 

 1884 : "in sinking a well in the Ganges for one of the piers of the 

 railway bridge at Benares, when the well was burst by a sudden 

 influx of water from below a bed of clay rising to a greater height 

 than the river water outside the well." 1 



(5) Borings in other tertiary rocks. 

 It is only in Gujarat that the tertiary rocks of India have been 

 specially examined in search of water, but it 



Boring for oil at r J 



Sukkur. ma y De mentioned here that one of the deepest 



borings in this country was sunk in tertiary strata in search of oil at 

 Sukkur. Some of the most successful artesian wells in America, 

 for instance those in Ohio, were originally experimental borings for 

 oil. The Sukkur boring, however, yielded neither oil nor water 

 (excepting a small flow at a depth of 865 feet), but it must be noticed 

 that all the strata encountered were clays and compact limestones 

 of a very impermeable nature. The boring reached a depth of 

 1,042-6. A complete record has been published by Mr. T. D. La 

 Touche. 2 



As already mentioned in the separate descriptions, it is possible 

 that the Karani, Coconada and Akyab borings although commenced 

 in the alluvium entered tertiary rocks at a certain depth from the 

 surface. 



1 " Further considerations upon Artesian sources in the plains of Upper India. 

 Rec. Geol. Surv. Ind., Vol. XVIII, p. 11S. 



2 " Report on the Experimental Boring for Petroleum at Sukkur, from October 1893 to 

 March 189.5." Rec. Geol. Surv. Ind.. Vol. XXVIII, pp. 55-59. 



( 75 j 



