Ch. XIII.] 
DERANGEMENT IN THE CRAG STRATA. 
177 
rows had occupied. Many grains of sand were drifted along 
the slopes a b, and c d, which, when they fell over the scarps 
b c, and d e, were under shelter from the wind, so that they 
remained stationary, resting, according to their shape and 
momentum, on different parts of the descent. In this manner 
each ridge was distinctly seen to move slowly on as often as 
the force of the wind augmented. We think that we shall 
not strain analogy too far if we suppose the same laws to 
govern the subaqueous and subaerial phenomena ; and if so, 
we may imagine a submarine bank to be nothing more than 
one of the ridges of ripple on a larger scale, which may increase 
in the manner before suggested, by successive additions to the 
steep scarps. 
The set of tides and currents, in opposite directions, may 
account for sudden variations in the direction of the dip of the 
layers, as represented in the wood-cut, No. 33, while the 
general prevalence of a southerly inclination in the Crag of 
Suffolk may indicate that the matter was brought by a current 
from the north. 
We may refer to a drawing given in the first volume*, to 
show the analogy of the arrangement of the submarine strata, 
just considered, to that exhibited by deposits formed in the 
channels of rivers where a considerable transportation of sedi- 
ment is in progress. 
Derangement in the Crag strata. — In the above examples 
we have explained the want of parallelism or horizontality in 
the subordinate layers of different strata, by reference to the 
mode of their original deposition ; but there are signs of dis- 
turbance which can only be accounted for by subsequent move- 
ments. The same blue and brown clay, or loam, which is often 
perfectly horizontal, and as regularly bedded as any of our 
older formations, is, in other places, curved and even folded 
back upon itself, in the manner represented in the annexed 
diagrams. 
* Chap, xiv., Diag. No. 6. 
Vol. III. N 
