4;G4! THE GEOLOGIST. 
fine sand, witliout pebble?, exhibiting every appearance of having been de- 
posited by water ; most frequently stratified, but sometimes unstratified. 
It has generally t^svo well-marked terraces above the waters of the present 
rivers, as well as some minor terraces. On the top of this is generally 
found about three or four feet of silty loam. 
2. Forest smul and gravel. — A deposit of sharp forest sand, parted with 
layers of gravel of same rocks as IS^o. 1, and having every appearance of a 
regular deposit by water, distinguishable only from jSo. 1 by its being 
iig. 1. 
found at greater elevations, containing more sand, and being generally 
more regularly stratified. It sometimes contains thin beds of till " lying in 
it, and much drifted coal. 
3. Till. — "Till," a mass of strong brown clay, in which are mingled the 
same kinds of rocks as those in Ts"os. 1 and 2, of sizes from six tons in 
weight to small pebbles, some rounded and partly rounded, and others 
quite angular, especially coal-measure and magnesian limestone rocks, with- 
out any order of deposition, great and small stones being mixed together 
indiscriminately, quite impervious to water, and well known as valuable 
brick clay, and from its being the deposit which yields striated or scored 
stones. Several beds of fine laminated silt and patches of sand are foimd 
in it. 
4. Lower gravel. — A bed of sand or coarse gravel, having the pebbles 
(consisting of the same kinds of rocks as Kos. 1, 2, and 3) well rounded, 
sometimes, but not always, occurring under the brick clay, often stratified, 
and at other times unstratified. It afifords good springs of bright water. 
Probably the deposits mentioned above will not always be found in the 
perfect order there laid down^ no doubt some of them may be wanting at 
places, especially Xos. 4 and 2, which have often been removed. 
The kind of gravel found here is somewhat similar to that in the north 
of France yielding fiint implements. ]\Iauy things have been found in 
these gravels, but have always been considered of doubtful origin. Some 
of the old beds of the course of the present river Irwell have been dug 
out, but little attention has been given to collecting anything from them. 
It is to be wished that attention were directed to these lowest terrace beds, 
with a view of ascertaining whether they contain any flint implements or 
fossil remains. Mr. Earr had stated that he had found a marine shell 
{Cardium edule) in the gravel of Stockport. On the top of the gravel is a 
iDed of silt, three or four feet thi-ck, and this seems to have been derived 
from floods, when the river overflowed its banks and deposited the silt. 
In the upper teiTace there are very often found thin beds of peat, and beds 
of silt between. 
The great body of gravel, about the level of the waters of the Irwell, has 
been moved about in the valley as the river has changed its course from 
time to time. A singular curve of the river occurs below Kersall Moor, 
which shows that the river may have gone straight across from Douglas 
mill to the place where the present suspension bridge is erected, a few 
hundred years ago, for the river on the Salford side is now encroaching 
on the Broughton side, and the Broughton side is encroaching on that of 
