360 <A. J. Jukes-Browne—Gramite in a Boring at Bletchley. 
is to suppose that boulders and blocks of the latter rock are here 
imbedded in the Kellaways sandstone. 
This explanation would necessitate our assigning a thickness of 
more than fifty feet to the Kellaways Beds, which is more than 
usual, but Mr. H. B. Woodward tells me that these beds vary 
considerably in thickness, and that there would be nothing surprising 
in their having a depth of 50 feet. We might indeed expect them 
to be thicker than usual at a locality where they included large 
blocks of a foreign rock. On this supposition, moreover, the 
occurrence of an ordinary clay at the bottom of the boring is 
naturally accounted for; whereas if the material above were assumed 
to be a massive igneous rock, its presence would be anomalous and 
very difficult to explain. 
It has already been mentioned that springs of saline water were 
found at depths of 390 feet and 410 feet. Mr. A. Timmins has 
kindly furnished me with analyses of these waters, and they happen 
to supply further evidence that the beds from which they issue 
belong to the Kellaways group. The analyses show 340 grs. and 
392 grs. of solid matter in the gallon, the following being the 
principal ingredients : 
Highest Lowest 
Spring. Spring. 
Combined chlorine ...............seeee 75:00 91-40 
Sulphuric anhydride .................. 108-08 123-24 
Calciumyoxrdeneeeeeescecceeteeece sees 20°02 9°98 
Magnesium oxide .............000-00s 4-89 4°37 
Residue principally soda. 
These proportions are equivalent to about 123 grains of sodium 
chloride in the highest water, and 150 grs. in the lowest, with 162 
grs. of sodium sulphate in the first, and 185 grs. in the second. 
My attention has been called to a Report on Bedfordshire well- 
waters by Dr. C. E. Prior to the Rural Sanitary Authority of the 
Bedford District (1888), in which mention is made of a band of 
‘“‘saliferous rock” which appears to extend with the Oxford Clay 
formation from the northern border of the parish of Kempton, across 
Wootton, and some way into Stanton.” He gives partial analyses 
of some of the well-waters which derive their supply from this rock, 
and the results show a remarkable correspondence with the Bletchley 
well-water. The amounts of total solid matter in solution vary 
from 188 grs. to 250 grs. per gallon. Chlorine is present in all of 
them, varying in amount from 388 grs. to 92 grs. per gallon. Sul- 
phurice acid is present in several and sulphurous acid in one. Thus 
at Lower Shelton Marston, which is not many miles north-east of 
Bletchley, a well-water contained 209°8 ers. of solids per gallon, 
72:1 being chlorine and 47:8 grs. being sulphuric anhydride. Dr. 
Prior comments on the very large quantity of sodium chloride which 
these waters appear to contain. 
There can be little doubt that the saliferous rock of Dr. Prior is 
one of the beds in the Kellaways group, for all the places he 
mentions are situate on the lower part of the Oxford Clay. 
To sum up, the information available with regard to the boring at 
