OCTOBER 13, 1899.] 
ent only the first of these has penetrated 
the secondary rocks, reaching coal measures 
ata depth of 1,580 feet below the surface ; 
the others have reached various horizons in 
the lower Cretaceous and Jurassic strata, 
which are found to thicken rapidly south- 
ward. Professor Boyd Dawkins concluded 
from the evidence of these borings that the 
southern boundary of the concealed coal- 
field in the eastern part of its course ranges 
nearly under the scarp of the South Downs, 
and that to the south of this the paleozoic 
floor is probably composed of rocks older 
than the coal measures. 
The concealed coal fields of another part 
of England—viz., North Staffordshire— 
were discussed by Mr. Walcot Gibson, of 
the Geological Survey, whose recent in- 
vestigations have shown that the so-called 
Permian rocks which overlie the pro- 
ductive measures at the margin of this 
field should be considered as part of the 
earboniferous system, since they are con- 
formable to the upper coal-measures and 
contain a coal-measure flora. By working 
out the details of these rocks, Mr. Gibson 
has been able to show that on the north- 
western side of the Staffordshire anticline 
the productive coal-measures are likely to 
occur within reach further west than might 
have been expected, thus increasing con- 
siderably the workable area of this coal 
field. It is interesting to find that these 
results have been attained by the minute 
study of strata which in themselves do not 
possess any direct economic value. Another 
stratigraphical paper with a practical ap- 
plication was that of Professor Boyd Daw- 
kins on the geological conditions of the 
proposed channel tunnel. The reading of 
this paper was followed by a brisk discus- 
sion, in which it was generally acknowl- 
edged that, apart from political reasons, 
there was not likely to be any serious diffi- 
culty in driving the tunnel through the 
lower beds of the chalk from England to 
SCLEN CE. 
509 
France. In the division of structural geol- 
ogy, Mrs. M. M. Gordon, D.Sc., contributed 
an analysis of the principles which underlie 
the complicated phenomena of folding to be 
found in the mountainous regions of the 
earth’s crust. 
As befitted the place of meeting, coast 
erosion received much attention from the 
section, three papers on this subject being 
read. Of these the most valuable was that 
of Mr. W. Whitaker, F.R.S., who summa- 
rized a large number of reports made by the 
coastguards all around the Kingdom as the 
result of circulars of inquiry sent out by the 
council of the Association with the sanction 
of the government authorities. This re- 
search promises eventually to yield highly 
important results in regard to the rate of 
destruction of our coasts by marine erosion. 
In the department of paleontology, with 
the exception of one or two reports of com- 
mittees, the papers were unimportant, while 
petrological science was represented mainly 
by a highly suggestive contribution by Pro- 
fessor A. Renard, of Ghent, on chondritic 
meteorites, in which it was pointed out that 
the rock structure of these visitants to our 
planet indicated that the parent mass had 
been subjected to the action of meta- 
morphism in a manner similar to that of 
some of the rocks of the earth’s crust. 
A paper brought forward by Professor P. 
F. Kendall gave the result of some recent 
researches into the course of underground 
streams in the limestone district of North- 
west Yorkshire; by the methods adopted 
the underground course taken by the prin- 
cipal sources of the river Aire have been 
more or less definitely traced. 
The address of the President of Section 
D (Mr. Adam Sedgwick, F.R. 5.) reviewed 
the facts of variation in their relation to 
reproduction and sex. Mr. Sedgwick con- 
tended that the variability of organisms 
must have been progressively greater the 
further we go back from the present time— 
