Notices of Memoirs — W. Traill 463 



in question of the water supply. He stated that the area occupied 

 by permeable formations capable of yielding water in wells sunk in 

 suitable situations was no less than 26,687 square miles, which, 

 receiving a rainfall averaging 30 inches a year, would yield up to 

 wells not less than 6 to 15 inches, or a daily quantity of not less 

 than 200,000 gallons for each square mile of surface, or a total 

 quantity far in excess of that required by the population of England 

 and Wales. The great value of these supplies for the towns and 

 districts of the Midland districts was insisted on by reason of their 

 purity, and from the absence of strong Parliamentary opposition, 

 which is encountered in all large gravitation schemes, whether the 

 water be proposed to be taken from natural lakes, as in the scheme 

 for Manchester, or from artificial reservoirs, as in the proposal for 

 Liverpool. The well-boring at Bootle, near Liverpool, completed 

 for the Liverpool Corporation by Messrs. Mather and Piatt, was 

 described as of great interest, the boring having reached a depth of 

 1,000 feet without reaching the base of the New Eed Sandstone. The 

 Committee expressed a hope that this boring may be continued, as it 

 will settle several questions, not merely of local interest, but of 

 national importance. 



VI. — On the Eocks of Ulster as a Source of Water Supply.^ 

 By W. Traill, M.A.I., F.E.G.S.I., of the Geological Survey of 

 Ireland. 



THE author first contrasted the backward state of the study of 

 hydro-geology in Ireland with its advanced progress in England. 

 The necessity for better water supplies had been recognized by the 

 larger towns, which had accordingly been supplied, but too many of 

 those, with populations of 5,000 to 1,500 inhabitants, were still 

 supplied only by shallow surface wells, a source universally con- 

 demned as scarcely possible to be free from sewerage pollution, the 

 fruitful parent of disease. The two great systems of water supply 

 were contrasted, that by catchment basins with large reservoirs, 

 and that by deep wells or borings, the latter where practicable being 

 undoubtedly considered the best. The rocks of Ulster were then 

 reviewed with regard to their suitability as sources of water supply. 

 The Lower Silurian rocks of Down, Louth, Armagh, and Monaghan 

 did not possess the essential qualities necessary for success ; neither 

 did the granitic tracts of Mourne, Newry, or Eathfriland, nor the 

 metamorphic rocks of Donegal and part of Londonderry, nor the 

 districts of the Carboniferous Limestone. The New Eed Sandstone 

 formation, one of the great sources of water supply in England, was 

 shown to occupy in Ulster a A^ery limited surface area, in some 

 districts yielding water by boring, and likely to prove productive 

 in other places also, but requiring special selection of sites for 

 operations. The Chalk and Hibernian Green sand formations were 

 shown to be the great water-bearing rocks of Ulster, as evidenced 

 by the large number of perennial springs along their outcrop. The 

 geological basin of the Cainozoic in the counties of Antrim and 



Eead before the British Association, Dublin, in Section C, August 19, 1878. 



