1874]. Geology. 127 
examined hundreds of sections of the loess, and had never found any fresh- 
water shells, but myriads of uninjured land shells. 
Mr. W. T. Blanford has brought forward evidence of glacial action in Tropical 
India in early geological times. Some peculiar beds, possibly of carboniferous 
age, consisting of large boulders, embedded in a fine silt, were considered by 
him as evidence of glacial action; the deposition of the boulders being due to 
the agency of ice. 
Professor Von Baer has recently written a memoir on the Caspian Sea, to 
which Dr. Carpenter has drawn attention. Instead of the Caspian being 
intensely salt, like the Dead Sea, its waters had only about one-third of the 
usual saltness of ordinary sea-water. This was due to the precipitation of 
the salt in the lateral lagoons, where great beds were forming. These salt 
pans drained off the saline substances, and thus left the water pure. 
Professor Herschel and Mr. G. A. Lebour have made some experiments 
upon the conducting power for heat of certain rocks. Of all the rocks ex- 
perimented upon, shale resisted heat the most, whilst the metamorphic rocks 
were the best conductors. The experiments showed that the rates of conduc- 
tivity of heat through rock-masses depended on the structure of the latter. 
A thick bed of shale would arrest it. Hence, denudation of rocks, if carried 
on to any great degree, would alter the quantity of heat conduded from the 
interior of the earth to the surface. The experiments threw considerable 
light on underground temperatures. 
The Rev. O. Fisher, in‘a note on the “ Origin of the Estuary of the Fleet, in 
Dorsetshire,” expresses his opinion that it is the eastern half of a submerged 
valley, similar to, though on a larger scale than, the one which now forms the 
Weymouth Backwater, its former western side having been encroached upon 
and destroyed by the waves of the Weat Bay. ,; 
Mr. G. H. Kinahan has lately described the Water Basin of Lough Derg, in 
Ireland, and discussed the method of its formation. He points out that the 
bays and all wide stretches across the basin conform with the strike of lines 
of breaks or displacements in the adjoining country, while the minor features 
of the coast lines are due to the weathering along minor breaks, joint systems, 
or lines of bedding. It seems that in this basin all the changes in the 
bearings of the different lines of deeps are connected with the strikes of the 
different faults in Slieve Bernagh and Slieve Aughta, and that the islands, 
rocks, and shallows are on the upthrow sides of these lines of faults. 
It appears, from a despatch of the British Vice-Consul at Rhodes, that a 
volcanic outburst has taken place in the island of Nissiros, one of the 
Sporades, in which there existed a volcano supposed to be extin@&. Shortly 
before the roth June, 1873, new craters opened in this volcano, and from them 
ashes, stones, and lava were ejected; many fissures, from which hot water 
flowed, were produced in the mountain, and the island was daily shaken by 
violent earthquakes. From Rhodes, at a distance of about 50 miles, the smoke 
rising from the new craters could be seen. 
Stratigraphical Geology.—Mr. W. Whitaker (assisted by J. B. Jordan) has 
prepared a large block-model of London and its neighbourhood on a scale of 
6 inches to 1 mile, coloured to show the geology of the area, which includes 
Hampstead, Wimbledon, Great Ilford, and Shooter’s Hill. All the superficial 
deposits are represented, and the subterranean geology to a depth of 1100 feet 
is shown on the sides of the model, which is divided into nine pieces. This 
model is placed in the museum at Jermyn Street. 
Perhaps the Sub-Wealden Exploration is the most important topic in British 
geological circles. Commenced in 1872, the depth at present reached is a 
little over 300 feet. The boring commences about 230 feet down in the known 
Purbeck Beds, the thickness of which previously known in Sussex was some- 
what over 300 feet ; according to Mr. Topley, about 230 additional feet of strata 
have been made known by the boring, and in this series are some valuable 
beds of gypsum. Professor Phillips has communicated the latest intelligence 
in regard to the boring, stating that the lowest beds now reached are of marine 
