their for 
j 
1886.] Geology and Paleontology. 373 
Triassic—The geological age of the yellow sandstones lying 
north of the city of Elgin (Scotland) has been much debated, strat- 
igraphists having maintained that they belonged to the Devonian 
(or rather Old Red sandstone), while palzontological evidence 
is in favor of their Triassic age. The Lacertilia are represented by 
Telerpeton, Hyperodapedon and an undescribed form, Crocodilia 
by Stagonolepis, and Dicynodontia by the type genus. Dr. Judd 
and Dr. Gordon have now procured good evidence that this rep- 
tiliferous sandstone passes down into a bed of conglomerate 
which rests unconformably upon the strata of the Upper Old Red 
sandstone. The conclusion is that during the vast periods of the 
Carboniferous and Permian, the Upper Old Red sandstone of the 
Elgin area was upheaved and denuded, and the Upper Trias beds 
deposited unconformably upon their eroded surface. ; 
Jurassic and Cretaceous —MM. Bertrand and Kilian, who have 
studied the Jurassic and Cretaceous strata of Andalusia, report 
that their composition is very like that of the same beds in the 
Alps. There are also many analogies between them and the cor- 
responding beds of Sicily and of the Apennines, while the upper 
beds resemble those met with in the Balearic islands. The brach- 
lopod beds of the Middle Lias and the ammonite beds of the 
l VEA are met with alike in Sicily, the Apennines and parts of 
e Alps. 
interesting notes upon the causes of the purity of Nile mud. 
f ts mud, brought down chiefly by the Atbara and the Blue Nile 
“a a country of siliceous and crystalline rocks, is, like that of 
remaining in a perfect state. Professor Heim, known as one 
the best authorities on glaciers, states that the motion of a 
S’acier is, to a preponderating extent, the result of gravity. He 
enumerates partial internal liquefaction, caused by pressure; plas- 
MoT, y _ "e ice as it approaches the melting-point ; ruptures and 
oe t displacements, alternating with partial regelation and sliding 
and » aS Sources of glacier motion. Glaciers merely smooth _ 
. A slightly wear away the previously existing rough sur- — 
» while streams and sub-aérial weathering have given valleys — 
m. The glacier is more of a carrier and rubbish-remover _ 
a delver and ploughman. | 
than of 
