181 



but that in consequence of the angle presented by the latter, and the 

 distribution of their component materials, a subsequent elevatory 

 movement has taken place, to which he ascribes the difference of level 

 between the deposit and the present shore. 



A paper was afterwards read, entitled " Observations on the Dilu- 

 vium of the vicinity of Finchley, Middlesex 3" by Edward Spencer, 

 Esq., F.G.S. 



The district occupied by this deposit extends from Muswell Hill to 

 Finchley Common, a distance of about three quarters of a mile : its 

 breadth is about 150 yards, and its average thickness is from 15 to 

 20 feet. The best point for examining the deposit is at the gravel- 

 pits in the lane leading from Muswell Hill to Colney Hatch. It pre- 

 sents, immediately beneath the vegetable soil, a bed about 14 feet 

 thick, consisting of marl and waterworn fragments of granite, por- 

 phyry, micaceous sandstone, mountain limestone, coal, lias, oolite, 

 and chalk, with many of the characteristic fossils of these formations. 

 The most abundant pebbles are lias and chalk ; the latter being in so 

 great quantity as to give the whole accumulation a chalky character. 

 Flints are likewise sufficiently numerous to be extracted for repairing 

 the roads. 



This bed is separated by a well-defined line from another of red 

 gravel, about six feet thick, resting upon London clay. It is com- 

 posed of rounded chalk flints and sand, and saurian vertebrae are 

 occasionally found in it ; but no remains of Mammalia have been no- 

 ticed either in it or the superior bed. Mr. Spencer states that there 

 appears to be, in the whole of the deposit, a total absence of" the 

 .small rounded pebbles of Lickey quartz, which are plentiful on the 

 summits of the neighbouring hills of Highgate and Hampstead : and 

 in conclusion he suggests that the current of water which brought the 

 materials of the upper bed into their present situation flowed from 

 the north, 



March 25. — William Tite, Esq., Honorary Secretary of the London 

 Institulioii, of Upper Bedford Place 5 Robert Phippen, Esq., of Badg- 

 worth Court, near Cross, Somersetshire; Lieut. Cautley, of the Ben- 

 gal Artillery, Superintendent of the Doab Canal; William Hulton, 

 Esq., of Hulton, in Lancashire; and George Edward Eyre, Esq., 

 Barrister at Law, Lincoln's Inn Fields; were elected Fellows of this 

 Society. 



A paper was read, entitled " Remarks on the Structure of large 

 Mineral Masses, and especially on the Chemical Changes produced 

 in the Aggregation of Stratified Rocks during different periods after 

 their deposition ;" by the Rev. Adam Sedgwick, F.G.S. , Woodwardian 

 Professor in the University of Cambridge. 



§ 1. Introduction. 

 The first section of the paper is devoted to some general considera- 

 tions of the changes produced both by igneous and aqueous agents. 

 Changes of the former class may be effected in a comparatively short 

 period, and can sometimes be imitated in a laboratory. But changes 



