n- 
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614 LOWER OOLITIC ROCKS OF ENGLAND'. 
In reference to this saline water, Prof. Prestwich has expressed the 
opinion that it " has its origin in the New Red Sandstone, and not in the 
Oolitic or Liassic Strata, as would otherwise, from the depth of the boring, 
be the natural inference. If the water were from the Oolitic strata we 
should expect to find it much purer, and its solid matter to consist chiefly 
of carbonate of lime : if from the Marlstone or Lias, to be more ferruginous 
and calcareous."* 
At Holt, between Melksham and Trowbridge, saline waters were 
discovered towards the close of the 17th century in sinking a well. An 
account was published by H. Eyre,f who states that the water contained 
" mixed salts," in the proportion of 3 drachms, 1 scruple, and 19 grains 
in 1 gallons of water (= about 146 grains per gallon) ; no particular 
analysis, however, was given. The details of the strata passed through 
were noted by the Rev. J. Lewis as follows : 
f " After they had passed the upper turf they came to a blue Clay, 
which held about 3 foot ; then they met with a yellow, brittle Clay, 
very much like ochre, used by painters, about 2 foot in thickness ; 
and next with a loam of a looser texture, which sparkled with a kind 
of talc, called by the naturalists Selenites, and was intermixed with 
yellow ochre. . . . 
' ' Below this, at about 10 foot deep, they came to a bed of stones, 
of a large size, and very hard texture [Septaria] . . . 
"Here the springs come in, and below this the Clay was darker 
coloured, and interlaid with small shells of the Oyster, Escallop and 
Muscle kind, and with a few Belemnites curiously shaped. Here 
they met with stones of a very close texture ; which when washed 
seemed to be nothing but a mass of shells jumbled and embodyed 
J;ogether."J 
In connection with this subject it is interesting to note that saline or 
orackish water was also met with in a well made at Trowbridge (1870). 
The well was sunk 160 feet and bored 40 feet " into Lias." The water 
was found to contain the following ingredients : 
Total solid impurity (in parts per 100,000) - 144 34 
Chlorine - - 36 '70 
The following appears to be the only account of this well at present 
published: "In sinking the shaft a salt spring was tapped and after 
wards stopped out, but we were informed that some water came in at 
about 20 feet from the surface. Our analysis * * * shows the 
water to be excessively hard, and to contain a considerable proportion 
of common salt (6 Ibs. in 1,000 gallons, 3 oz. in this volume of water being 
about the usual proportion in good potable water), besides a rather large 
proportion of organic elements. " No details of the strata are given. 
The well was probably commenced in the Cornbrash (if not Oxford Clay), 
and if carried into the Lias, it shows a great diminution in thickness of 
the Lower Oolitic strata. It is very likely, however, that the term 
" Lias " was that used by the well-sinker, and the well was simply carried 
through the Forest Marble into the Great Oolite. 
The Melksham Spa derives its saline waters from, a well sunk (1815-16) 
through the Oxford Clay, Kellaways Beds, and Cornbrash into the Forest 
Marble, the depth being 351 ft. 6 in. It contains 552 grains of saline 
matter, chiefly chloride of sodium, in the gallon. 
Saline waters were met with at Swiudon in a well-sinking made by the 
Great Western Railway Company at their works (1883-85). || The forma- 
tions proved were as follows : 
* Prestwich, Ashmolean Soc., 1876. Analysis by W. F. Donkin. 
f A brief Account of the Holt Waters in Wiltshire. 12mo. 1731. 
J Phil. Trans, vol. xxxv. p. 489 (1728). 
Sixth Report of the Rivers Pollution Commission, pp. 105, 405. 
|| H. B W., Quart. Journ. Geol. Soc., rol. xlii. p. S87 ; and Taunton, Proc. 
Cotteswold Club, vol. ix. p. 61. 
