346 [Proc. B.N.F.C., 



ence of the basin-like depression below the trappean area, the im- 

 pervious beds relied upon as forming the basin must be the Lias 

 clays of the Keuper marls of the New Red Sandstone. Either are 

 sufficiently impervious to retain the water ; so that, in the possible 

 or probable absence of the Lias, the marls will be sufficiently re- 

 tentive. Our basin being admitted, it is evident cannot hold 

 water above the level of its margin, and if the basin is tilted the 

 level of its lower edge will be the level of the contained water. 

 Now, we know that while the New Red Sandstone marls 

 maintain a tolerably uniform level on the west, south, and 

 east boundaries, it drops below the sea to the north of the 

 country; and therefore, the level of the contained water in 

 this our basin must stand at or about the sea level. Again, the 

 entire trappean area is traversed by intersecting dykes in every 

 direction, materially intercepting the uniform flow of the under- 

 ground waters, and complicating in a most serious manner the data 

 upon which we have to rely in estimating the probable supply from 

 any one locality. But, granting the existence of an unbroken 

 basin, full of pure water, to what level will the water rise in a boring, 

 say at Ballymena? — after all, the practical value of any boring de- 

 pends upon this. Clearly, we cannot rely upon the existence of 

 any artesian system, because we have no impervious bed overlying 

 the permeable water-bearing strata. These and other considera- 

 tions may very fairly prompt any session of County Antrim rate- 

 payers to question, if not absolutely refuse to entertain, any scheme 

 for the supply of water to towns from deep wells. 



Mr. Gray next referred to the valuable work done by the Geo- 

 logical Survey, but stated that the benefit resulting to the public 

 was hindered by the high prices at which the maps and memoirs 

 were issued. Mr. Gray then alluded to the caves of Fermanagh. 

 In that county the limestone hills are traversed by rivers which 

 frequently disappear into the ground and burst out again at the 

 opposite side of the mountain. The effect of these waters is that 



