172 Notices of Memoirs—Short Notices of Memoirs. 
really an important fact as establishing the former wide geographical 
distribution of forms now confined almost solely to one or the other 
of the two continents.” In the district under consideration, it appears 
that the loss is confined to elevated plateaux, its upper portion is 
broken up, contorted and commingled with glacial drift, and the 
whole is overlain by unmodified glacial drift. The authors consider 
that the loss was deposited in an ice-bound basin, the coldness of the 
waters and the low temperature of the air, being attested by the 
depauperate shells found imbedded in it. The observations of the 
authors indicate the unipartite character of the drift-sheet above the 
léss, and lead them to disbelieve in the hypothesis of a ground- 
moraine and a superficial moraine being formed by each glacier ; 
finally, from the disappearance of the blue colouration downward in 
certain sections of drift clay, they conclude that this colour is not 
normal but is changed to brown or yellow by oxidation from above. 
5. Mr. W. J. Harrison, in a paper ‘“ On the Quartzite Pebbles con- 
tained in the Drift, and in the Triassic Strata of England; and on 
their Derivation from an Ancient Land Barrier in Central England” 
(Proc. Birmingham Phil. Soc. vol. iii. p. 157, 1882), has treated of 
a subject of great interest to English geologists. Describing first 
the lithology, he passes on to enumerate the fossils obtained in the 
pebbles, which belong to Lower and Upper Silurian and Devonian 
species; and it is remarkable that the Orthis Budleighensis is the 
most abundant fossil in the quartzite pebbles at Birmingham, and 
also at Budleigh Salterton. Mr. Harrison says: “It seems perfectly 
clear that the quartzite pebbles, which occur so abundantly in the 
Drift of the Midland Counties, were derived from the Pebble-bed or 
Conglomerate which forms the middle member of the Bunter Sand- 
stone, or Lower Trias.” The author discusses the origin of this 
conglomerate, and points out its formation from the Paleozoic axis of 
the Midlands. An appendix giving a list of papers on the subject, and 
another by Mr. J. J. H. Teall on the microscopic structure of certain 
specimens of Quartzite, complete this very carefully prepared paper. 
6. “ On the Geological Effects of a Varying Rotation of the Earth” 
(American Naturalist, Jan. 1883) is the title of a paper by Prof. 
J. E. Todd. The forces tending to accelerate rotation are, the con- 
traction of the earth, and the transfer of matter (in the form of ice, 
sediment, etc.) from lower to higher latitudes. The retarding in- 
fluences are, the friction of the tides, the transfer of matter from 
higher to lower latitudes, elevation of the earth’s crust in lower 
latitudes, and distortion of the earth’s body by the attraction of the 
sun and moon. The author enters into a brief theoretical view of 
the action of these forces. He then proceeds to compare the theory 
with recorded facts relating (1) to changes during the present epoch, 
(2) to changes in the early Quaternary period, and (8) to changes 
in earlier ages. In conclusion he indicates certain important lines 
of investigation in connexion with the subject. 
7. Dr. Charles Barrois has described the Raised Beaches on the 
west coast of Finistére (“Sur les plages soulevées de la cote occidentale 
du Finistere,” Ann. Soc. Géol. du Nord, vol. ix. 1882). In connexion 
