Transportation of Floating Sand. — Simonds. 29 
and snowy climate so induced the growth of the ice-sheets to 
their demonstrated thickness of a mile or more is attributable. 
The time of accumulation and extension of the ice was doubt- 
less long, in comparison with its generally rapid final melting, 
which is known from many features of the drift deposits of 
that time". Instead of the preglacial high altitude, both these 
continents stood at nearly their present hight, or in the drift- 
bearing portions mostly 100 to 500 feet lower than now, when 
the ice melted away; and this closing or Champlain epoch of 
the Ice age seems to have depended on the subsidence of the 
land from its previous great hight. 
Not onl3 T were the borders of the ice-sheet thus rapidly 
melted back, giving an increased steepness of the frontal 
slope and faster glacial flow, as compared with the time of 
maximum glaciation; but also the influence of the warm 
climate properly belonging to the low altitude, apparently 
having nearly as high mean annual temperature as now on 
the same latitude, further reinforced the vigor of the ice cur- 
rents by the facility of molecular change of the ice grains 
and flow of the whole mass toward its waning boundary. The 
rapid accumulation of the moraines, even those of largest 
size requiring probably only a few decades of years, is readily 
accounted for by the double effects of the steeper gradients 
and the warm temperate climate. We are enabled to see how 
the fast flow of the Arctic glaciers terminating in the sea is 
consistent with very slow movement of the ice border on con- 
tiguous high land ; and why the sluggish ice action of the 
time of farthest glacial advance was followed by the ener- 
getic moraine-forming glacial currents of the Champlain 
epoch, that is, the time of subsidence of the land and final 
recession of the ice. 
FLOATING SAND: AN UNUSUAL MODE OF RIVER 
TRANSPORTATION. 
Bj Frederic W. Simonds, Austin, Texas. 
On the eighth day of August last 1 joined a camping party 
at Bessemer, on the Austin and North Western railway, 93.75 
miles from Austin, in Llano county, Texas. This station is 
on the Llano river, a (dear Stream, tributary to the Colorado, 
flowing through what has been termed " the Central Mineral 
