462 



NATURE 



[Sept. 7, 1882 



mid Districts from these Formations. Drawn up by C. E. De 

 Ranee, Secretary. — Eight years have elapsed since this Com- 

 mittee commenced to investigate the circulation of underground 

 waters, and the quantity and character of water supplied to 

 towns and districts so derived. 



From 1S74 to 1S78 the Triassic and Permian formations were 

 alone under consideration ; in that year the Jurassic rocks were 

 added to the scope of the inquiry, w hich at the York meeting 

 was enlarged to include the w hole of the permeable rocks in 

 England and Wales. 



The Triassic and Permian rocks of Devonshire are described 

 in the first, fifth, and sixth reports ; of Somersetshire in the 

 first ; of Leicestershire in the first, fourth, and fifth ; of Warwick 

 in the second, fourth, and seventh ; of Nottingham in the second 

 and sixth; of Cheshire in the seond, fourth, and fifth; of 

 Lancashire in the firsf, second, third, fourth, sixth, and seventh ; 

 of Yorkshire in the first, second, third, sixth, and seventh ; of 

 Shropshire in the jixth. 1 



Through the removal to South Africa of the member of the 

 Committee taking charge of Staffordshire, this district is still 

 incomplete, but srme information as to the Burton-on-Trent 

 area is given in the first report. 



In Devonshire the inquiry was carried on by Mr. Pengelly, 

 F.R.S., supplemented by details obtained by Mr. Stooke, C.E. 

 The Triassic rocks of the district have been made the object of 

 careful study by Mr. W. A. E. L'ssher. From his investigations 

 it would appear that the equence exhibited has more in common 

 with the Trias of the Fiench side of the English Channel than 

 with that of the midland counties. In Devnn-hire and Somer- 

 setshire the sandstones and conglomerates appear to have been 

 deposited in a distinct basin to that north of the Mendips, the 

 Keuper marls being alone common to the two districts. 



The basin south of the Mendips is remarkable for having a 

 series of marls intercalated in its sandstones, called by Mr. 

 Ussher the " Middle Marls " ; these underlie sandstones beneath 

 the Ktuper marls- The conglomerates hnea distinctly local 

 character, and when present are plentifully water-bearing, as are 

 the sardstor.es, though to a somewhat less extent. 



Private supplies are obtained by wells at Torquay, where the 

 water-level is 168 feet above the sea ; at Teignmouth ; at Daw- 

 lish, where the water-level is 71 feet above the sea; and at 

 Bramford Speke, near Exeter. 



Near Exeter the Lyons Holt spring issues at 126 feet above 

 sea-level, yielding towards the town supply 47,000 gallons 

 daily of very pure water, which is extensively used for drinking- 

 fountains. 



Higher up the valley of the Exe and its tributaries private 

 supplies are obtained at Crediton. 



North is the watershed separating the streams flowing into 

 English and Bristol Channels. 



At Wellington a well 230 feet above the sea is sunk to a depth 

 of 48J feet ; only a small quantity of water is pumped from it. 



At Taunton numerous private wells give a supply of rather 

 hard water from the New Red Sandstone. 



At Somerton hard water is obtained from a well 129^ feet 

 deep ; the White Lias is said to occur in it at 90 to 99 feet. 



At Wembdon a private well in triassic conglomerate yields 

 hard water at a well 30 feet deep, at 60 f> et ab^ve the sea. 



At Wookey, near Wells, 70 feet above the sea, a private well, 

 33 fett, yields a constant supply, uninfluenced by the seasons as 

 to quantity, tut decreases 9 feet in level after dry weather. 



In Bristol the wells vary in depth from 60 to 300 feet, some 

 only penetrating peat and gravel, others passing through triassic 

 marls, whilst a few penetrate the Coal-measures. 



At Braysdown Colliery, near Bath, a shaft 500 yards deep, 

 passing through New Red Sandstone and Coal-measures, yielded 

 water at the bottom of the pit containing 100S grains of common 

 salt, or 1440 parts per 100,000. 



In the Tiverton Coal-pit, near Bath, 16,800 gallons per 24 

 hours are yielded by plastic shale in the Blue Lias, 130 feet above 

 the White Lias, which is 12 feet thick, resting on 23 feet of 

 Kluxtics, lying on the New Red Marl; the water contains 112 

 parts per 100,000 of common salt. 



The Tyning Pit, Radstrck, intersected a spring yielding 

 864,000 gallons per day at 200 feet from the surface, at the 

 bottom of the Red Marls. 



1 Report of British Association for 1875 (Bristol) contains first report : that 

 for 1876 (Glasgow) the second : that for 1877 (Plymouth) the third ; that for 

 1878 (Dublin) the fourth; that for 1879 (Sheffield) the fifth; that for 1SS0 

 (Swansea) the sixth ; and that for 1SS1 (York) the seventh. 



At Kilmersdon New Coal Shaft, Writhliigton, a 10 fret shaft 

 intersected a spring at 253J feet. On cutting through a hard 

 base of stone the water rose 99 feet in 24 hour-, and stands at 

 this level, yielding 98,400 gallons per day of hard water. The 

 section pas ed through was liassic clay, black and blue marl 7S 

 feet ; 34 feet of "red ground," with 1 lands of 1 lue stone; con- 

 glomerate 5 feet ; red beds 4 feet ; then conglomerate again ; 

 the remainder of the section is not given. The la'e Mr. Charles 

 Mcrre considered the last, 5 feet 4 inches of the I.ias, in this 

 section to belcng to the Rhsetic beds. 



In reference to the information furnished by Mr. Taunton as 10 

 the Thames and Severn Canal, it may be well to state that the 

 outcrop of the oolitic rocks has an average breadth on the dip 

 of 25 miles. The base of the Oolites resting on the lias reaches 

 its highest point near Chipping Campden, 1032 feet above the 

 sea, on the watershed between the Thames and Severn ba-ins. 

 This, >outh of the Severn Well', the source of the Churn, runs 

 somewhat east of the ba>e of the Oolite, cau-ing the sur- 

 face drainage of the oolitic tract around Minchinhampton, 

 Dursley, and Wotton-under-Kdge to flow into the bain of the 

 Severn. It is probable also that a portion of the underground 

 drainage does so al-o, notwithstanding the general south-easterly 

 dip, from the basement level of the Oolites, varying in the 

 direction of the strike, owing to the denudation of the escarp- 

 ment being unequal, the Oolite to the south having been worn 

 back much further down the dip, and consequently to a low er 

 elevation than at Chipping Campden, descending from 1030 at 

 the latter place, to 212 feet in the Stroud Valley, or about 8co 

 feet in 25 miles. South of this valley the level rises ; lightly, 

 so that a partial discharge of underground drainage takes plate 

 in this valley, which is immediately west of the point in the 

 Thames and Severn watershed which is penetrated by the canal 

 connecting the two basins. 



Of the 25 miles of average outcrop of oolitic rocks measured 

 on the dip, only about 8 consist of impermeable depo its : — 

 viz. the Fuller's Earth, the Oxford Clay, and the Kimmerid.e 

 Clay — so that two thirds of the area may be considered to be of 

 a permeable character. 



Warwickshire information. — The southern and western por- 

 tion of the Warwickshire coalfield is overlaid by Permian rocks 

 consisting of reddish-brown and purple sandstone-, intercalated 

 with marls in lenticular beds, rising to a heigt t of 622 feet at 

 Cowley Hall, which forms part of the watershed between the 

 tributaries of the Trent to the North, and those of the Avon 1 n 

 the south. 



Though the surface-drainage of this Permian area flows in 

 opposite directions, that portion of the rainfall percolating into 

 the ground has a uniform gradient to the south, the base of the 

 Permians, where they rest on the coal-measures west of Ather- 

 stone, being 470 feet above the sea, and 170 feet under the 

 Mifhurst Tunnel of the M inland Railway, bein^ a fall of 50 feet 

 per mile, while at Warwick the tops of the Permians are 186 

 feet above the sea, and as they are not less than 800 feet thick, 

 their base is probably about 600 feet below the >ea-ltvel, giving 

 a furtherr fall of 7S6 feet in iS miles, or a fall of 43 mile--. 



Examining the district more minutely, it is seen that though 

 the Permians donot always lie conformably on the coal-measures, 

 yet there is a general conformity, and a synclinal flexure tra- 

 versing the coal-measures from north to south is shared by the 

 overlying Permians, which have synclinal dips towards the axis 

 of an average amount of 3°, or about 270 feet per mile from the 

 edges of the basin towards the axis, which recurs more to the 

 eastern than the western margin. 



The fault throwing in the coal measures of Arley Wood is 

 believed to be connected with the fault throwing back the rut- 

 crop of the main part of the coal-field at Broomfield Park ; but 

 of this there is no evidence, and as the dips in the Permian show 

 the fiYxures to be present on b'.th sides of the supposed fault, 

 its existence is very doubtful. If it occurred, and were a water- 

 tight barrier, the water percolating into the sand-tones to the 

 west of Atherstone and flowing south would be thrown out in a 

 line of springs, which is not the case ; and there is no doubt that 

 the waters travelling in the porous portion of the system flow 

 south to Leamington and Warwick, where a portion of the 

 supi ly is utilised. South of this point the Permians are con- 

 cealed by triassic, liassic, and oolitic rocks in the direction of 

 Bambury. S< uthwards the Permians probably wedge out bef re 

 the Trias, which continue into the Thames ba--in, the water 

 travelling down the dip planes of the Permian, where that for- 

 mation thins out, probably enters the overlying triassic sands, 



