MR. H. B. WOODWAED ON A WELL-SINKING AT SWINDON. 301 



[or rather to ooze out] above the original level of the field," The 

 water on examination was found to contain 552 grains of saline 

 matter in a gallon, and this seems to have been chiefly sodium 

 chloride, together with magnesium and calcium chlorides, calcium 

 sulphate, magnesium and calcium carbonates, and ferric oxide. 



In 1815 "the lEelksham 8pa Company" was formed, and in 

 order to procure an abundant supply of saline water, another well 

 was sunk in a field to the east of the old saline spring. The record 

 of this weU has been published, and from the account of the strata 

 there can be no doubt that the Oxford Clay and Kellaways Rock were 

 passed through, as well as the Cornbrash, and that the waters, as at 

 Swindon, welled up from the Forest-marble. It may therefore 

 be interesting to quote the full account of this well-sinking. 



After having dug one hundred feet they commenced the process 

 of boring, under the superintendence of Mr. Brough, an able 

 engineer, who after twelve months' labour, on the 1st of March, 

 1816, obtained the much-desired object. Since that date one hundred 

 feet more were sunk. 



The following are the particulars of the various strata, in the 

 words of the engineers : — 



f "A series of marl, dark-coloured, ninety feet thick, which in the 

 digging broke into rhomboids, 



" Then marl again, about one hundred and thirty-two feet thick, 

 varjdng in colour ; most of this presented in every fracture or section 

 which could possibly be made, a glut of the remains of marine organized 

 bodies, among which were many of the Cornu Ammonis, most beautifully 

 gilt with the pyrites of iron, assuming every metallic lustre imaginable. 

 I The Nautilus also often occurred. The specific gravity of this mass was 

 considerably greater than that of the foregoiiig, owing to its containing 

 much iron. Towards the bottom of this marl thin irregular beds of 

 jet were met with ; also, some large turtle-formed stones, which were 

 extremely hard. [Septaria.] 



" Next a layer of stone two feet thick, in hardness equal to granite. 

 ^ " Marl again, in thickness fifty feet, colour as above. 

 m ( " Afterwards stone, two feet six inches thick, moderately hard, but 

 5 ,__, differing from any of the foregoing, being more granulated, and, when 

 %% \ tried between the teeth, exceedingly gritty, 

 ^ o j " Then marl, in thickness eighteen feet. 



H Ph I « Tijg character of this marl was also different from any of the above, 

 & \^ being more indurated, as also gritty. 



i "3" f " Next stone, in thickness twenty feet, moderately hard, and of a 

 o % \ lighter colour than any preceding. This was divided into about eight 

 2jp [ strata, by thin beds of clay, from one inch to two and a half thick. 



'' " Then alternate strata of stone and clay, imited thickness twenty- 

 1-7 three feet six inches ; the beds of clay from six to twelve inches. 

 g ^ "Afterwards a bed of stone two feet six inches thick. This was 



a § ■{ whiter than any yet met with, and moderately hard. 

 ^ g " Stone succeeded, eleven feet in thickness, very hard, and separated 



'— ' I into about five or six strata, by beds of clay mixed with a little sand ; 

 ^ these beds were from one to four inches thick. 



" Total depth from the surface, three hvmdred and fifty-one feet 

 six inches." 



After the borer had penetrated the eleven feet of stone, &c., it 

 entered a bed of sand, and the water " gushed forth, in quantity 



