1891.] Geology and Paleontology. 483 
Plistocene, and was at least one of the causes of the cold, and there- 
fore of the ice-accumulation ; (2) that the increasing load of ice was 
the main cause of subsidence below the present level; (3) that the 
removal of the ice-load by melting was the cause of the re-elevation 
to the present condition ; but (4) that all these effects lagged far behind 
heir causes.” (Bull. Geol. Soc. Am., Vol. II., pp. 223-330.) 
Submarine Channels of the Pacific Coast.—JIn a recent 
paper in the Bull. Geol. Soc. Am., Prof. Joseph LeConte discusses the 
submarine channels off the Pacific coast, The researches of Professor 
Davidson have brought to light twenty or more submarine channels on 
the coast from Cape Mendocino to San Diego. The distinctive feature 
of these, as contrasted with those on the eastern shore, is that they 
have no obvious relation to existing rivers. They are not a submarine 
continuation of any system of river valleys on the adjacent land. On 
the contrary, they run in close to shore, and abut against a bold coast, 
with mountains rising in some cases 3,000 feet within three to five 
miles of the shore-line, and wholly unbroken by any large river valleys. 
Mr. LeConte thinks it is impossible to account for this except by 
orogenic changes which diverted the lower courses, and places of 
emptying of the rivers, since the channels were made. He dates these 
changes about the end of the Pliocene or beginning of the Plistocene ; 
they were probably coincident with the lava-flows and consequent dis- 
placement of the rivers, which took place at that time in the Sierra 
region. 
Geological News.—Walter Harvey Weed has been working up 
the geology of the Cinnabar and Bozeman coal fields of Montana. He 
believes that facts warrant him in stating that these Coal Measures are 
of Laramie age. They are conformably overlain by volcanic material 
containing an abundant fossil flora of recognized Laramie types, in 
turn overlain by beds of fresh-water clays and sandstones of undeter- 
mined age, but which belong to what has heretofore been considered 
as undoubtedly Laramie strata. (Bull. Geol. Soc. Am., Vol. II., pp. 
349-364.) According to E. T. Newton, the rodents now known to 
occur in the brick-earth of the Thames valley are: Castor fiber Linn., 
Spermophilus erythrogenoides Falc., Microtus (Arvicola) amphibius, 
Linn., Microtus (Arvicola) ratticeps Key. and Bl., Myodes torquatus 
Desm., and M. lemmus Linn. (Geol. Mag., Vol. VII., Dec., 1890.) 
According to Mr. Robert Bell, ore bodies of the nickel and cop- 
per deposits in the Sudbury (Canada) district do not appear to have 
been accumulated like ordinary metalliferous veins from mineral 
