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TRANSACTIONS OF SECTION C. 1041 
Specimens were also taken from the bare slopes and precipices near the sea, 
where the junction can be more clearly seen. 
The specimens picked up along the line of junction consisted of granite studded 
throughout with angular fragments of basalt, which fact appears to indicate the 
posteriority of the granite. 
Taken by themselves these specimens would seem to point to the conclusion that 
the granite had been erupted at a later date than the gabbros, and that the molten 
granite had included the shattered fragments of an older rock in it. 
The main question which the specimens would appear to suggest is —‘ What 
are the respective ages of the granites and gabbros?’ 
The specimens in my opinion appear to point to the posteriority of the granite, 
and one specimen shows a vein of granite piercing the basalt. 
3. Eleventh Report on the Circulation of Underground Waters in the Per- 
meable Tormations of England and Wales, and the Quantity and 
Character of the Water supplied to various Towns and Districts from 
these Formations.—See Reports, p. 380. 
4. On Deep Borings at Chatham: a Contribution to the Deep-seated Geology 
of the London Basin. By W. Wuiraker, B.A., F.G.S., Assoc.Inst.C.E. 
A few years ago the Admiralty made a boring in the Chatham Dockyard 
Extension, to the depth of 9034 feet, just reaching the Lower Greensand, and in 
1883-84 followed this by another boring, near by, to increase the supply, which 
has led to an unexpected result. After passing through 27 feet of Alluvium and 
Tertiary beds, 682 of Chalk, and 193 of Gault, the Lower Greensand was again 
reached ; but, on continuing the boring, was found to be only 41 feet thick, when 
it was succeeded by a stiff clay, which, from its fossils, is found to be Oxford Clay, 
a formation not before known to occur in Kent. 
At its outcrop, about seven miles to the south, the Lower Greensand is 200 
feet thick, and is succeeded, a little further south, by the Weald Clay, there 600 feet 
thick. Not only, however, has this 600 feet of clay wholly disappeared, but also 
the whole of the next underlying set of deposits, the Hastings Beds, which crop 
out everywhere from beneath the Weald Clay, and are also some hundreds of feet 
thick. 
More than this, the Purbeck Beds, which underlie the Hastings Beds near Battle, 
are absent, and also the Portlandian, Kimmeridge Clay, Corallian, &c., beds which 
have been proved above Oxford Clay in the Subwealden Boring, to the great thick- 
ness of over 1,600 feet. 
We are therefore faced with a great northerly thinning of the beds below the 
Gault, a fact agreeing in the main with the evidence given of late years by various 
deep wells in and near London. 
Three other deep borings have been made or are being made near Chatham, all 
of which have passed through the Chalk into the Gault, and one has gained a supply 
from the sand beneath, 
The practical bearing of the Chatham section is, however, to enforce the danger 
of counting on getting large supplies of water in the London Basin from the Lower 
Greensand, by means of deep borings at any great distance from its outcrop. 
Even if Lower Greensand occur at all in such places, it will probably be in re- 
duced thickness, and therefore with reduced water-capacity. 
5. On the Waterworks at Goldstone Road, Brighton. 
By W. Wuitaknr, B.A., F.G.8., Assoc.Inst.0.E. 
Notes of a visit underground in December 1884, when the water was pumped 
down for extending the galleries. 
These works are perhaps the best example of the right way of getting a very 
1885. 3X 
1% 
qs 
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