Fune 19, 1873] 
NATURE 
195 
principal valleys, but sometimes crossing watersheds, indicate a 
great confluent glacier-sheet,, at one time almost covering a 
great part of the district, the movement of which was determined 
by the principal water-shed of the Lake-district. In the part of 
the Lake-district under consideration the ice, during its increase, 
carried forward, from south to north, a great quantity of rocky 
material. There are no signs in the district of the occurrence of 
mild periods during the epoch of primary glaciation, but the 
author thought that the climate had probably become moderate 
before the great submergence of the land commenced. The 
author noticed the effect of the submergence upon the results of 
previous glacial action, and maintained that when the Jand had 
sunk 800 or goo ft. there was a recurrence of cold, and boulders 
were transported by floatingice. Until the submergence reached 
1,500 ft. there was no direct communication between the northern 
and southern halves of the Lake-district except by the straits of 
Dunmail Raise. From the directions which would be taken by 
the currents in the sea at this period, it would appear that 
boulders may then have been transported by floating ice in some 
of the same directions as they had previously been carried 
by glacier-ice. The extreme of submergence appeared to have 
been about 2,000 ft. The author further maintained that fon 
the re-elevation of the district there was a second land-glaciation, 
affecting the higher valleys and clearing them ef marine drift.— 
** Alluvial and Lacustrine Deposits and Alluvial Records of the 
Upper Indus Basin,” by Frederic Drew. The author said that 
he felt the necessity fora careful classification of the phenomena 
of alluvial deposits, for the want of recognition of the different 
kinds was likely to lead to incorrect deductions; the classifica- 
_ tion he proposed was the following :—I. Loosened material, which 
consisted of disjointed rocks or loose angular stones, sometimes 
mixed up with mud, which had been separated and disinte- 
grated, but since that had remained unmoved. IL. Taluses, the 
substance of which had fallen by its own weight, and not been 
transported by streams. These were the great heaps of angular 
matter that were found at the foot of cliffs, with a slope gene- 
rally of near 35°. A special form was the fan-talus, which 
occurred where the falling matter had either originated from, or 
collected to, one spot, from which again it spread, and made a 
partial cone of the same slope as the ordinary taluses. III. 4//u- 
vial Fans.—These were the fan-shaped extensions of alluvial or 
torrential matter that spread out from the mouths of gorges, 
where these debouched into a more open valley. They were in 
form cones of a low angle, commonly 5° or so; they had accu- 
mulated by layer after layer on a cone-shaped surface, as shown 
by the radial sections exhibiting layers of a straight slope, and 
the chord sections showing curves, which were by the theory 
hyperbolas. Many complicated phenomena were produced by 
the denudation of these fans, and the production of secondary 
ones, some of which were illustrated by diagrams. IV. A//u- 
wium, which was defined as a deposit which sloped down the 
direction of the valley of the stream which had made it, and did 
‘not appreciably slope or curve over in a direction at right angles 
to that. With regard to the country in question, there was 
evidence of a succession of three states :—Ist, The cutting of 
the valleys. 2nd, The accumulation of alluvial matter. 3rd, 
The cutting down of the streams through that alluvial matter. 
Accumulation denotes an excess of supply of material from the 
rocks (by disintegration) over what can be carried away by the 
streams. Denudation, or the cutting down of the streams through 
their alluvium (the lowering of their beds), denotes a deficiency 
of supply of material from the rocks as compared with the trans- 
porting power of the streams. Hence the author inferred that 
the period of great accumulation of these alluvial deposits was 
one of great disintegration of rocks, one of intense frost ; in other 
words, it was the Glacial period, and that the denudation occurred 
when the cold lessened, and there came to be a smaller supply 
of disintegrated material. The connection of various glacial 
phenomena with the alluvium, such as the one described above, 
was taken to corroborate the inference that the greater deposits 
were made during the Glacial epoch. 
Geologists’ Association, June 6.—Mr. Robert Etheridge, 
F.R.S., vice-president, in the chair.—‘‘On Ammonite Zones in 
the Upper Chalk of Margate, Kent,” by Mr. F. A. Bedwell. 
The author described, and showed by sections, the exact po- 
sitions in the cliffs to the east and west of Margate, of fifteen 
large Ammonites, twelve of which lie between the Flagstaff and 
the Cliftonville Hotel, a space of about half a mile, and some 
~ of them exceed three feet in diameter. All these twelve are in 
a bed closely approximating to an exact parallel with a faint line 
a 
of nodular flints which undulates over this part of the cliff and 
are at a constant distance of eight feet below that line. These 
facts indicate the following (1) The presence of an Ammonite 
zone, and of (2) a true sea floor. (3) The parallelism of this 
with the horizontal flints, and (4) that all the horizontal bands of 
flint must be assumed to have been aggregated before the chalk 
moved. Particulars were also given of three other beds of Am- 
monites, one to the west of Margate, another forty feet below 
that first mentioned, and a fourth at Pegwell Bay, at the top of 
the cliff near the landing-stage. The first and second were con- 
jectured to be identical, and also the third and fourth. Specimens 
from the first and second beds were respectively identified by 
Mr. Etheridge as A. Jeptophyllus and A. Lewesiensis. Similar 
beds elsewhere were referred to, but details could only be given 
of one, This is to be seen at low water near the Black Rock 
at Brighton. A remarkable bed of continuous solid flint, 
three or four inches thick, occurs round and under the Isle 
of Thanet. Between the Foreland and Pegwell Bay it is 
in the upper part of the cliff, sinks below the shore at 
Pegwell Bay and Kingsgate, rises again to the west at 
the back of Margate Harbour but disappears immediately, 
appears again to the south, as pointed out by Mr. Whitaker in 
his Geology of the London Basin, at Cap Point near Walmer, 
and again at Shepherd’s Well Station, 10 miles inland, where it 
is surmounted by the soft almost flintless chalk of Margate, and 
finally it was known throughout the island by the well diggers. 
This positive testimony of coincident and uniform flint aggrega- 
tion over so large an area appeared to be an important fact in its 
bearing on the origin of flint. Mr. Bedwell stated that he had 
found the ammonites entirely by trusting to the zone of life 
theory insisted on by Mr. Caleb Evans in his paper on the Chalk 
(Geol. Assoc, 1870), and had failed to find them until he had 
selected the faint line of flints as a datum line and worked from 
that. He advised all young students of the chalk to examine a 
cliff in true horizons and not in a mere indiscriminate effort to 
make a large bag of specimens, to record carefully the exact 
chronological order of each fossil extracted by referring it to a 
datum line as suggested by Mr. Caleb Evans, to keep in mind 
the time which may have separated the life history of two fossils 
though only distant a few feet from each other, and to try to 
correlate two sections of chalk rather by the succession of zones 
of life in each cliff than by a mere comparison of indiscriminately 
collected fossils. The author in conclusion urged the importance 
of allowing Nature to teach her own independent lessons at the 
cliff side, of supplementing Nature by books rather than books 
by Nature, and pointed out how easy it was for thase with little 
knowledge of details to be of service to science by simple obser- 
vation and following to its end one single thread and one only, 
and then laying the results before scientific men, leaving them to 
estimate the value of the information. 
Royal Horticultural Society, June 4.—Scientific Com- 
mittee.—A. Smee, F.R.S., in the chair,—A fruit of Anona re- 
ticulata was sent produced in the gardens of Sir Walter Tre- 
velyan at Wallington.—A letter was read from Prof. Westwood, 
stating that some grubs which had been submitted to him as 
having completely destroyed some bulbs, proved to belong to 
Merodon clavipes, a very rare insect in England, and in this case 
probably introduced.—A Pelargonium of the variety Cleopatra 
was exhibited from the Chiswick Garden, It had produced 
trusses of flowers of its proper pink as well as others of its an- 
cestral scarlet,—Dr. Gilbert made some remarks on the proposed 
use of chalk mixed with coal in furnaces for horticultural pur- 
poses. He said it was quite certain the chalk could not supply 
any heat ; on the contrary, its conversion into lime involved a 
considerable loss of heat in order to effect the change. What 
the chalk did was to absorb the heat and radiate it out again, 
and pieces of broken fire brick would probably answer the pur- 
pose equally well. The mixture of these substances simply, so 
to speak, diluted the coal.—A fine specimen of fasciated aspara- 
gus was shown from Mr. Macmillan. It has been produced two 
years running apparently from the same plant. 
General Meeting.—Viscount Bury, M.P., president, in the 
chair.—The Rey. M. J. Berkeley stated that he had recently 
seen in Denbighshire nectarine trees, the flowers of which usually 
produced five carpels instead of one. He commented on the 
effects of the late frost on the potatoes at Chiswick. Some were 
very much injured, while others had escaped altogether, and in 
some instances of two stems to one root, one had been killed 
back and the other not touched. 
