A Deep-Sea Boring at Kilacheri. Silks 
January 20th.—Sir Archibald Geikie, D.C.L., D.Sc., Sec.R.S., 
Vice-President, in the Chair. 
The following communications were read :— 
1. ‘On the Jaws of Ptychodus from the Chalk.’ By. Arthur 
Smith Woodward, LL.D., F.R.S., F.L.S., F.G.S. 
2. *On the Igneous Rocks at Spring Cove, near Weston-super- 
Mare. By Willam 8S. Boulton, Esq., B.Sc., A.R.C.S., F.G.S8. 
A traverse from end to end of the exposure at the locality shows. 
that the ‘ basalt-mass’ varies in structure and appearance, and 
that it is by no means a simple lava-flow. It may be roughly 
divided into three portions. Beginning at the cliff-end to the 
north, the rock for the first 30 yards is a pillowy basalt, with 
tuff and limestone often occupying irregular spaces between the 
spheroids of amygdaloidal basalt; then, for about 20 yards, the 
rock is mainly a coarse ‘ agglomerate,’ with lapilli and bombs of 
basalt and limestone ; while the remaining 100 yards or so is an 
ordinary basalt-coulée, with very few and always small lumps of 
burnt limestone. The limestone below is reddened and altered, and. 
although tuffy-looking, does not contain indubitable lapilli; the lime- 
stone above contains lapilli. The pillowy basalt probably represents 
a river of agglomeratic material carrying finer lapilli, larger and 
plastic masses of scoriaceous basalt, and lumps of limestone, possibly 
ejected from a vent. The intervening tuff may present an analogy 
with the ‘volcanic sand’ of the West Indian eruptions. There is 
no evidence of the quiet deposition of ashy material, but rather of 
the tumultuous aggregation of a fluxion-tuff taking place under 
some depth of sea-water. The large and irregular fragments of 
limestone, oolitic and fossiliferous, found mainly in the lower part 
of the basalt-mass, have not come in from above through cracks in 
the lava, but seem to have been picked up while in a soft and 
powdery state from the sea-bed in which it had been accumulating, 
and to have been involved with and altered by the volcanic 
material. The conditions existing in submarine flows appear to 
be very like those in a sill or intrusive sheet. 
February 3rd.—Sir Archibald Geikie, D.C.L., D.Sc., Sec.R.S., 
Vice-President, in the Chair, 
The following communications were read :— 
1. ‘On a Deep-Sea Deposit from an Artesian Boring at Kilacheri, 
near Madras,’ By Prof. H. Narayana Rau, M.A., F.G.S. 
The village of Kilacheri is about 6 miles due south of the 
railway-station of Kadambattur. Here permeable beds of sand- 
stone and felspathic grits dip at low angles seaward, and are 
overlain by impervious clays and shales. The boring, after pene- 
trating the upper clays and sandstones, passed through carbonaceous 
shales, and at a depth of about 400 feet reached a blue homo- 
geneous rock, effervescing with agid and showing radiolarian tests 
under the microscope. Most of the latter display the inner 
