Correspondence. 433 
Having shown the inefficiency of land ice he attributes the wonderful 
-examples of planation, scojing and grooving to sea-ice, floe-bergs, and 
glaciers accelerated by flotation, and presents a full array of all published 
observations that seem to favor that conclusion. This forms another val- 
uable feature of his paper. 
The paper shows an anti-glacial bias of some strength. While this may 
stimulate to closer observation in that direction, it has apparently hindered 
in the opposite, and so prevented really correct conclusions. We find no 
reference to the observations and conclusions of Prof. A. Geikie and his 
associates, who visited some of the same localities and on the same errand 
in 1865. They came to quite contrary results. It would have been well 
-if he could have at least attempted a harmonizing of ideas. 
His inference that land-ice never sculptures its rocky bed with its em- 
bedded boulder seems weakly supported. For, it rests largely on the 
assumption that its velocity is alvvays insignificant, at least not surpassing 
that of the Norway glaciers observed, which by his own showing are 
small and decrepit. Besides, how can the great velocity observed in the 
seaward end of glaciers exist without a closely corresponding rate above 
the sea level? And even, if we allow the limitation of velocity assumed, 
the case is not proved. May not the boulders in the cases observed have 
melted their way through the ice? For the conducting power of rock is 
about twice that of ice, and would not the relations in this respect be very 
difEerent, near the edge of the ice and the warm earth beyond, and in the 
remote depths of a great ice sheet ? 
In conclusion we feel grateful to the professor for the forcible way in 
which he presents the claims of floating ice upon the attention of geologists- 
Formerly too much was ascribed to its action. There came a reaction 
which we have little doubt has carried the pendulum of opinion too far in 
the opposite direction. Glacial theories have become dominant, and we 
might almost say tyrannical. Excavations, scorings and formations of all 
sorts and magnitudes have been ascribed to this one versatile and all- 
powerful agent. It seems quite clear that the efficiency of floating ice in 
similar directions has been largely overlooked. Here seems to be, there- 
fore, a nearly virgin field of investigation. Who will as patiently and 
thoroughly study this agency as Forbes and others have the glaciers ? Who 
will te)l us what is going on to-day in waters where this agency is at work? 
CORRESPONDENCE. 
Mitchell county, Texas. The Texas and Pacific Railroad, passing east 
and west through the centre of Mitchell county, crosses the Colorado river 
at Colorado City. The general course of the Colorado river through the 
county is south-east, revealing the "Red beds" throughout its course. 
These beds give character to the soil of the country and to the color of the 
water, that of the Colorado river being a deep brick red. The " Red beds " 
were carefully examined for fossils in many places, with but poor success. 
