774 T. C. CHAMBERLIN 
that in some cases there cis) Sovintimateman ‘association with 
marine deposits as to indicate that the ice reached the sea level 
and discharged icebergs. The associated marine fossils do 
not seem susceptible of explanation by mechanical admixture 
through the action of the ice, because of their condition and 
their position in the embracing sediments. Oldham’ reports 
that certain bowlder-bearing mudstones ‘‘contain delicate Fen- 
estella and bivalve shells, with the valves still united, showing 
that they had lived, died, and been tranquilly preserved where 
they are now found, and proving, as conclusively as the matrix 
in which they are preserved, that they could never have been 
exposed to any currents of sufficient force and rapidity to trans- 
port the blocks now found lying side by side with them. These 
included fragments of rock are of all sizes from a few inches to 
several feet in diameter.” 
These and other evidences leave little room to doubt that a 
part of the glaciation at least affected low horizons. On the 
other hand, most of the glacial beds are so related to their own 
glaciated floor as to show that they were formed by land ice. 
This is confirmed by the nature of the striz, the relations of the 
transported blocks to their source, and the association of the 
glacial beds with fresh-water deposits. At present some of the 
glacial beds are 3000 to 3500 feet above sea level (Tasmania), 
but in general they are much lower. How much of this altitude 
is due to subsequent changes I do not know. There is, however, 
much evidence that the glaciation was not of the alpine type, or 
at least not simply of the alpine type. It spread over broad 
areas of moderate slope. 
In kind of glaciation and in topographic relations the Paleo- 
zoic phenomena seem to have been of the same class as the 
Pleistocene. 
Approximate age.—Professor David and other cautious writers 
of recent date do not attempt to locate the horizon of this glacia- 
tion nearer than Permo-Carboniferous. It is certain that in the 
Salt Range in northwestern India a Productus fauna overlies the 
*R. D. OLDHAM: Rec. Geol. Surv. India, XIX, 1886. 
