420 Original Articles. [July, 



vertical descent beyond the density of the rock itself. What is true 

 of the rock as regards the facility of vertical percolation is true also of 

 lateral, so that in general the formation may be considered permeable 

 in every direction. The late Mr. R. Stephenson, whose views on^| 

 this question time and experience have only served to confirm, in hi^ 

 Report on the Supply of Water to Liverpool, says, " My opinion is, that 

 on considering the question of the supply of water, the rock (New 

 Red Sandstone) may be looked upon as almost equally permeable in 

 every direction, and the whole mass regarded as a reservoir up to a 

 certain level, from which whenever wells are sunk water will always 

 be obtained more or less abundantly." Such qualities are obviously 

 of the highest importance, because they enable a well of sufficient 

 depth to draw from long distances around, and thus to yield a large 

 supply. Thus the Green Lane Well, east of Liverpool, which by 

 sinking and boring reaches a total depth of 385 feet, and yields up- 

 wards of three millions of gallons per day, is stated by Mr. Dun- 

 can, the resident engineer, to have influenced wells several miles 

 distant. 



In the Midland Counties the formation consists either of a soft 

 variegated sandstone, or of a quartzose conglomerate, both nearly 

 equally porous, and available as sources of water-supply ; and of these 

 large areas occur in the neighbourhood of Birmingham, Stafford, Wol- 

 verhampton, Kidderminster, Derby, and Nottingham. 



The second important feature of the New Red Sandstone is its great 

 vertical thickness, especially in the counties of Cheshire, Lancashire, 

 and Salop, where it is over 1,000 feet. In the Central Counties the 

 thickness is less, and in the eastern parts of Leicestershire and 

 Warwickshire the rock thins out altogether. This thinning away of 

 the formation takes place from North-west to Soutli-east, and may be 

 thus expressed :— - 



Thickness in Feet. 



Lancashire and Cheshire 1,200 to 1,000 



Derbyshire, Staffordshire, Nottinghamshire . 600 to 150 



Warwickshire and Leicestershire . . . 150 to 



Hence it will be observed that there are parts of the country 

 where these water-bearing beds do not exist, and this is the case under 

 Rugby. 



With such a vertical development in the Central and North- 

 western Counties, we may conclude there is a somewhat pro- 

 portionately large horizontal area exposed to the rain-fall ; but 

 another consequence is the vast extent of storage-room thus afforded 

 by this formation ; both are necessary for the capability of yielding 

 large quantities of water, for a thin stratum, however widely spread 

 out, could never yield very large supplies. Now the area occupied 

 by the New Red Sandstone in the Counties above named is over 1,000 

 square miles, and with an average rainfall of 30 inches, we may as- 

 sume that every four or five square miles will be capable of yielding 

 one million of gallons daily.* Taking the latter figure, we have a 



* This rate of yield has been determined pretty well by several observations in 

 Lancashire and Cheshire. 



