Mackintosh— On the Lake-district. 303 
The termis ancient creeks, fiords, or voes (a name given to narrow 
inlets in Shetland) may be applied to most of the valleys of the 
Lake-district which are shut up at one end. When two valleys 
communicate by a col, they may have originated in a line of frac- 
ture; and Professor Harkness (see Quart. Journ. Geol. Soc., vol. xix, 
p- 128) regards Grisedale Valley, between Ullswater and Grasmere, 
as running along an anticlinal axis. But many of the valleys in 
Westmoreland and Cumberland present indications of being almost 
exclusively due to the undermining and excavating agency of the 
sea. As may now be seen in Shetland, the sea would appear to have 
made a breach in a cliff or declivity in a particular direction, nothing 
further being necessary to enable it to pursue its work of voe- 
making. In some of the Lake-valleys, as in that which runs up 
from Kirkstone Foot in a direction parallel to Deepdale, the sea has 
left a number of blocks—some of them just detached from the parent 
rock, others carried to a short distance; as if, by a sudden rise of 
the land, it had been stopped short in its career, that it might leave 
monuments not only of its work of denudation, but of the various 
steps by which that work was accomplished. 
Action of Rivers.—The streams which traverse most of the valleys 
of the Lake-district are too insignificant to justify the supposition 
that these valleys have been scooped out by running water since the 
last emergence of the land. In many valleys the level at which the 
action of the sea left off, and that of the stream commenced, can be 
traced in the abrupt commencement of the precipitous sides of the 
channel of the latter. A similar sudden break in the general slope 
of the sides of a valley, indicating the commencement of fluviatile 
as distinct from previous marine denudation, may be seen in Aber 
Valley, North Wales, and Ash’s Valley, Longmynd, Shropshire. 
The latter furnishes a striking instance of a winding and bifureating 
creek or voe. But in those river-gulleys which graduate upwards 
into larger valleys, we may often discover a sufficient distinction 
between their respective contours to justify our referring the one to 
fluviatile, and the other to marine denudation. Professor Sedgwick 
has noticed another kind of proof of the limited excavating power 
of rivers in the Lake-district, as being furnished by the small quan- 
tity of detritus they have yet been able to deposit in the lakes which 
receive their waters.* 
Origin of Cwms.—The Welsh word Cwm is applied to a distinct 
class of hollows, which seem to point more strikingly than either 
passes or ordinary valleys to the sea as the great excavator. Few of 
these hollows correspond in shape with the lithological structure of 
the district in which they are situated: they are hollows of denu- 
dation par excellence. It is true that some of them, when viewed 
* In connection with this subject, it is worthy of notice that there are many 
valleys and hollows of denudation in the Weald of Sussex with no streams flow- 
ing through them; while some of the valleys of Wiltshire and Dorsetshire present 
a series of raised beaches which embrace nearly the whole of the declivities on both 
sides, in such a way as to show that these valleys remain as they were left by the 
sea. 
