44 THE ESSEX FIELD CLUB. 



excellent work in this direction, if formed upon somewhat similar lines as the 

 Underground Water Committee of the British Association. Its function should 

 be to collect together every possible information and detail of a geological, 

 chemical, physical, engineering, and structural character. With reference to 

 wells, springs, and rivers, the mere bringing together of such information, and 

 tabulating the same in some standard form to admit of comparison, would be a work 

 of the highest value. This, it appeared to him, could be achieved without much 

 difficulty if members of the Club could be induced to assist, being distributed 

 as they are all over the county. Mr. Wood had endeavoured, in a private 

 c^ipacity, to get information for making a hydro-geological survey of the district 

 before mentioned, similar to what Mr. Lucas had done for parts of Kent and 

 Surrey, but met with so many difficulties that he gJ.ve it up after six months 

 work. 



Mr. Wood mentioned that the River Stour and valley was highly interesting 

 from a hydraulic point of view, and that several places existed where gauging 

 of the daily flow of the river could easily be obtained, as weirs already existed, 

 especially at Liston near Long Melford, where the mill has been removed and 

 the flow of the river is passing over a board fixed across the old wheel race ; but 

 unfortunately he knew of no one in the neighbourhood who would take sufficient 

 interest to make a daily gauging. 



He further mentioned the possibility that a large quantity of Chalk water 

 was discharged into the bed of the River Stour between Long Melford and 

 Bures, probably in the neighbourhood of Sudbury, Suffolk, where the Chalk came 

 to the surface. The river always appeared full between Borely and Bures, how- 

 ever dry the seasons might be ; and, what was more, the water was usually bright 

 and clear, except in flood time. Interesting results would no doubt be obtained 

 if the river was gauged between the points mentioned. 



From the results of the analyses in Dr. Thresh's paper, it appeared conclusive 

 that where the Chalk is overlaid with considerable thickness of Tertiaries (Lon- 

 don Clay, Woolwich Beds, and especially Thanet Sands), the water obtained 

 from the Chalk by means of a boring contained a much greater quantity of solids 

 and chlorine, besides being a softer water, than water obtained from a boring or 

 well sunk in the open Chalk. 



Mr. Wood instanced the following eight wells sunk down to the Chalk, and 

 mentioned in Dr. Thresh's paper, but overlaid w^ith a considerable thickness of 

 Tertiaries, viz., the three wells of the Southend Water Company, Brentwood 

 Asylum, Havering, Maldon Water Park Felstead, and Tiptree. The average 

 solids were 74, average hardness 2-9, average chlorine 21-5 ; whereas if the five 

 wells in the open Chalk were taken, viz., Saffron Walden, Sudbury (two), Hoddes- 

 don (two), the average solids were 35-9, average hardness 2o-6, average chlorine 

 27. 



The above differences w.re remarkable in water derived apparently from the 

 same formation. The only suggestion that one could offer was that the water 

 from the sands (especially the Thanet Sands) above the Chalk intermingled freely 

 with the Upper Chalk waters, due to the absence of impervious beds. 



In conclusion, Mr. Wood thought that it would probably be highly interesting 

 if Dr. Thresh could examine a series of waters (say taken in a line from Haver- 

 hill to Southend) from the open Chalk to where it is overlaid by a maximum 

 thickness of Tertiaries, and state the changes in the solids, hardness, and 

 chlorine, as the case mig^ht be. 



