PROCEEDINGS OF GEOLOGICAL SOCIETIES. 
465 
Salford at other points. From some of the old plans connected with the 
Broufifhton estate it is more than probable that evidence might be got as 
to what was really the course of the river 200 or 300 years ago, and thus 
show the rate of change of the river-course per year. Several acres of 
Salford are found on the Kersall side, and about the same quantity of 
Kersall on the Salford side of the river, clearly proving that there have been 
some singular changes since maps were made ; for the river was doubtless 
once the boundary line of the two townships. The waters in the valley 
there have, no doubt, been of much greater volume than they are at present, 
or tliey could not have removed the materials from the spaces between the 
terraces. 
The brick clay, or " till," has been proved to be thirty yards thick, and 
contains fragments and boulders from azoic and palaeozoic rocks of nearly 
all kinds, with a few secondary rocks. 
In the neighbourhood of Tib Lane, the bed of clay is parted with quick- 
sand, and the till seems gradually to go out and the quicksand to come in. 
This quicksand is found in several parts of Manchester. A singular fact 
^ in regard to the junction of the sand and the till 
•T^ ^l) ; - sometimes presents itself, namely, the wedge-like 
- -^(i nianner in which the sand sometimes enters the till 
Fig. 2. at the junction of the two (Fig. 2). 
The last bed of drift is the lower sand and gravel. This formation is 
not much seen in the neighbourhood of Manchester. It is only in sinking 
wells and boring holes that it is occasionally met with. It would be de- 
sirable to know what sort of fossils, if any, are to be found in it. The bed 
has been sometimes found to be ten or eleven yards thick. 
The Secondary beds found in the neighbourhood of Manchester consist 
of Trias rock. In some parts of the town it is from 200 to 300 yards thick. 
The palseozoic rocks are the Permian and Carboniferous. 
In the discussion which followed, Mr. Atkinson said it had occurred to 
him that this valley gravel was really marine gravel, and that there had 
been a communication with the sea up the valleys of the Mersey and Irwell. 
Manchester, he added, \A as very few feet above the level of the sea ; and 
the tide came even now to Warrington. 
Mr. Binney stated that most of the points even of the valley gravel are 
about 100 feet above the level of the sea. 
Mr. Hull dissented from the opinion that these valley gravels were of 
marine origin. He formerly entertained the opinion that they were, but 
there was one reason which he could advance which appeared to him to be 
decisive that they were old river terraces, and that was the fact that the 
slope of their upper surfaces coincides with the present slope of the river. 
If the valle}' gravels were old sea or marine gravels they would necessarily 
be very nearly horizontal, and at any rate the change in the level of the 
upper surface would necessarily be very slight, because in order that the 
sea should ascend to such a height as 160 feet above the present level, it 
would require a general submergence of land. 
Mr. Plant said he could corroborate the views of Mr. Hull relative to 
the freshwater character of the upper gravel, from excavations made when 
sinking for the foundations of the Museum in Peel Park. 
London Institution. — A very interesting course of six lectures, on 
** The Operation of Heat in the Production of Geological Phenomena ; 
with reference, principally, to those of Volcanos and Earthquakes," is now 
being dehvered by E. W. Brayley, Esq., F.R.S., F.G.S. The syllabus is 
so full that it will prove useful to many of our readers : — 
liECTURE I. {Nov. 1 2.) — Volcanos and earthquakes the most obvious manifestations of the 
VOL. V. 3 O 
