RECENT AND FOSSIL RIPPLE-MARK. 
IS 
to the excellent experimental work of Hunt, Darwin, and others 
which was designed to develop the principles underlying the 
formation of ripple-marks; but we are assured on the first page 
that “no one seems until now, to have definitely ascertained 
their cause.” This author denies that wind and waves have 
any power to produce ripple-mark and states that “Ripple- 
marks are the work of the tide and of that alone.” He concludes 
that ripple-marks are the product not of the direct action of the 
tidal current but of transverse currents which are accessory or 
incidental to the action of the tidal current with which they are 
associated. It is indeed surprising that he should forget that 
ripple-marks are formed on the bottoms of all small lakes with 
sandy beaches where tidal action is entirely absent and where 
wind developed waves are alone competent to produce them. 
The evidence furnished by the ripple-mark of any small lake 
directly controverts Dr. Epry’s statement that “There is no 
correlation between the movements of the aerial ocean and the 
wrinkling of the sandy surface submerged under a very thin 
stratum of water ” One of the essential premises on 
which this new theory of ripple-mark formation is based rests 
on the author’s observation that “On the upper beach ripple- 
marks are never found. They occur in contrast in great abund- 
ance on the lower beach . . . . ” With this observation as a starting 
point the author develops his theory that ripple-mark results 
from the interaction of the down-flowing currents of the upper 
steeper beach and the normal current of the lower less steeply 
graded beach meeting more or less at right angles to each other. 
It must be pointed out here, however, that this fundamental 
premise regarding the absence of ripple-mark from the upper 
beach is true only locally, I have observed on the uppermost 
part of the beach at Kingsport, N.S., perfectly developed ripple- 
mark where the beach is almost flat, so that no transverse current, 
such as Epry’s theory calls for, could have been developed. 
Epry’s statement that ripple-mark occurs only on the lower 
beach, though subject to numerous exceptions, is true for shores 
with a moderate tidal current; because during the first part of 
the ebb the direct current is too weak to produce ripple-mark. 
It is only on those parts of the beach which are uncovered after 
