PIIOCEEDTN-OS OF GEOLOOTCAL SOCIETIES. 



4G5 



Salford at other points. From some of the old plans connected with the 

 Broughton estate it is more than probable that evidence might be got as 

 to what was really tlie 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 ilie 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 douljtless 

 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 they 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 



^ s in regard to the junction of the sand and the till 



vP&^'T^ ^ZZ7 ^^~B ' sometimes presents itself, namely, the wedge-like 

 ■ manner in which the sand sometimes enters the till 



Fi'jr. 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 Avith. 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 palaeozoic rocks are the Permian and Carboniferous. 



In the discussion which followed, Mr. Atkinson said it had occurred to 

 him that this A^allcy gravel was really marine gravel, and that there had 

 been a communication M'ith the sea up the valleys of the Mersey and Irwell. 

 Manchester, he added, was 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 valley 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 wovdd necessarily be very slight, because in order that the 

 sea should ascend to such a lieight as IGO feet above the present level, it 

 would require a general s\d)mergence 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 PhenonuMui ; 

 with reference, ])rincipally, to those of Volcanos and ]^arthquakes." is now 

 being delivered by E. W. Brayley, Esq., F.E.S., F.G.S. The syllabus is 

 so full that it will prove usefid to many of our readers : — 

 Lecture I. {Nov. 12.) — Volcaiios and earthquakes the most obvious manifestatious of the 



VOL. V. So 



