A Boring near CricJdade, Wilts. 355 



BOREHOLF. AT CaLCCTT. 



Surface-level. — 260 ft. above ordnance-datum. Thickness. Depth. 



f^ f 1 ^, fl. Clay, with an occasional layer of ft. in. ft. in. 



Uxtord tlay -^^ septaria . . . . 193 6 193 6 



Rock 6 194 



Sand, grey, very fine-grained. 

 (Yielded about 30 gallons of 

 water jier hour, but the fine 

 Kellaways J sand hampered the pumps.) . 25 219 



Beds "^4. Clay, very hard . . . 13 2.32 



Sandstone, grey, calcareous, ex- 

 tremely hard . . . .18 250 

 Clay, apjoarently finer textured 

 than 1 and 4 . . . . 18 268 

 n. Limestone, bluish-grey, shelly, 

 Cornbrash - " mixed with clay " (see below) : 



( penetrated . . . . 5 273 



As the hole was " jumped " it was a difficult matter to obtain 

 proper samples of the rocks passed through, but satisfactory 

 specimens of beds 3, 5, and 7 were brought up. Those of the sand- 

 stone, bed 5, were of Kellaways Rock. Those of bed 7 were bluish- 

 grey, shelly (chiefly fragments of oysters) limestone, similar to the 

 well-known Forest Marble limestones. Mr. T. Rylands informed 

 me {in litt., 29th May, 1922) that he understood that this rock was. 

 " mixed with clay ". This remark, together with the appearance of 

 the limestone, is very suggestive of Forest Marble Series ; but if such 

 were the case the Cornbrash would be absent, because bed 5 is 

 definitely Kellaways Rock. Bat, as the Cornbrash is well de- 

 veloped along its outcrop near The Fosse ; as similar difficulty was 

 experienced in identifying it in the cores drawn at the Pumping 

 Station, Lewis Lane, Cirencester ; as when unweathered, deep 

 down, it would be of a bluish-grey colour ; and, as along its outcrop it 

 is often rubbly and mixed with some marly clay, I am disposed to 

 regard bed 7 as its subterranean continuation. 



The water obtained from bed 3 " proved to contain a large amount 

 of salt " (Mr. T. Rylands, in litt., 2nd May, 1922). It is a well-known 

 fact that water from the Oxfordian (Oxford Clay and Kellaways 

 Beds) is usually highly mineralized, and unfortunately it has been 

 established that waters in the Oolites, perfectly fresh when uncovered 

 by the Oxfordian, are as a nile mineralized when tapped beneath such 

 a covermg. Thus Mr. G. J. Churchward, the Engineer to the Great 

 Western Railway, informed the late W. W. Fisher that a year or 

 two previous to 1904 he tested by borings the waters beneath the 

 Oxford Clay from Swindon to Kemble (where the clay ends), and 

 found that the chlorine dimmished all the way to a point about 

 a mile and a half on the Swindon side of Kemble station.^ 



The Cornbrash did not yield any water worth speaking of, and as 

 that from the sand of the Kellaways Beds was inadequate, salty, and 

 the fine sand woald have proved troublesome for the pumps, the 

 borehole was abandoned. 



1 The Analyst, vol. xxix. No. 35, February, 1904, p. 37. 



