1874.] Geology. 415 
Caucasus, Crimea, Greece, and the South of Europe. In advancing south- 
wards through Russia a range of low drift hills occurs about 60° N. lat., which 
may perhaps form part of a circular terminal moraine left by a retreating polar 
ice-cap ; large grooved and polished stones of northern origin reach 55° N. lat. 
at Nijni Novgorod, but further east and south no such stones could be seen. 
The highest drift beds along the whole course of the Volga seem to have been 
arranged by water moving southwards. In America northern boulders are lost 
about 39°, in Germany about 55°, and in Eastern Russia about 56° N. lat., 
where the trains end, and fine gravel and sand cover the solid rocks. Ice- 
action, in the form either of glaciers or of icebergs, is necessary to account for 
the transport of large stones over the plains, and the action of moving water 
to account for drift carried further south. There are no indications of a conti- 
nuous solid ice-cap following southward over plains in Europe and America 
to, or nearly to, the Equator; but a great deal was to be found on shore to 
prove ancient ocean circulation of equatorial and polar currents, like those 
which now move in the Atlantic, and much to prove the former existence of 
very large local ice-systems in places where no glaciers now exist. 
Prof. Ramsay, in discussing the physical history of the Rhine Valley, stated 
his opinion that, during portions of the Miocene epoch, the drainage through 
the great valley between the Schwarzwald and the Vosges ran from the 
Devonian hills north of Mainz into the area now occupied by the miocene 
rocks of Switzerland. Then, after the physical disturbances which closed the 
Miocene epoch in these regions, the direction of the drainage was reversed, so 
that, after passing through the hill country between the Lake of Constance 
and Basle, the river flowed along an elevated plain formed of miocene depo- 
sits, the remains of which still exist at the sides of the valley between Basle 
and Mainz. At the same time the Rhine flowed in a minor valley through the 
upland country formed of Devonian rocks, which now constitute the Taunus, 
the Hundsruck, and the highland lying towards Bonn, and by the ordinary 
erosive action of the great river the gorge was gradually formed and deepened 
to its present level. In proportion as the gorge deepened, the marly flat mio- 
cene strata of the area between Mainz and Basle were also in great part worn 
away, leaving the existing plain, which presents a deceptive appearance of 
having once been occupied by a great lake. 
Pale@ontology.—A new genus of corals has been founded by Dr. Nicholson, 
under the name of Duncanella, in compliment to Prof. Duncan, of King’s 
College. The specimens of this coral have been found in the Lower Silurian 
rocks of Indiana. 
Mr. L. C. Miall, Curator of the Museum of the Leeds Philosophical Society, 
has published an excellent guide to the Fossil Collection in the Museum, which 
is in itself a capital elementary introduction to Palzontological Science: the 
principal groups of fossils, both plants and animals, are described, and their 
modes of preservation are pointed out, whilst numerous references are given 
to works which would prove useful to the student. 
Mr. Seeley has recently described a new genus of Plesiosaurians from the 
Oxford Clay, which he has named Mur@onsaurus. 
A new family of Paleozoic Brachiopoda has been established by Mr. David- 
son and Dr. King, which they call the Trimerellide. As far as is at present 
known they are confined to the Cambro-Silurian and Silurian systems. 
Sub-Wealden Exploration.—A total depth of 671 feet has now been reached, 
and the boring is still in the Kimeridge Clay. Mr. Topley, who has examined 
the specimens below the depth of 376 feet, reports that slight indications of 
petroleum have been noticed all through the clay. He has been able to record 
no less than twenty forms of Mollusca (the species cannot always be identi- 
fied) and some fish-remains. Ammonites biplex, Cardium, Modiola pectinata, 
and Lingula ovalis are the most abundant fossils in the Kimeridge Clay. It 
is not quite certain at what exact depth in the boring the Kimeridge Clay 
began, but it was probably about 290 feet from the surface, so that about 
380 feet of it have been penetrated. Its total thickness at Netherfield (near 
