Geological Society. ; 483 
shell limestone, angular pieces of greenstone, and contain 
organic remains belonging to older beds than the chalk: but 
as all these beds basset more or less to the W. of the place 
where the fragments are now to be found, the circumstance 
is considered “by Mr. Warburton as indicating an ancient 
current, the course of which was from W. to E, 
A paper entitled * Observations on Glen Tilt, ” by Dr. 
MacCulloch, V. P. G.S. was read. 
That part of Glen Tilt which is the subject of the present 
paper, extends four or five miles from Forest lodge to Gow’s 
bridge. It consists of primitive schist, assuming the ap- 
pearance of clay-slate, of mica-slate, and of hornblende- 
slate, with which are interstratified various beds of granular 
limestone, more or less micaceous. Near Gow’s bridge the 
stratification is perfectly regular and uninterrupted, but 
higher up towards the lodge it is traversed by granite rock, 
and an infinite multitude of granite veins of various sizes. 
Where this latter rock makes its appearance the even course 
of the schistus is interrupted in proportion to the magni- 
tude of the mass of granite. When the granite, schist, “and 
limestone are all in contact, a perfect confusion of these 
three substances takes place. Where the granite and lime- 
stone are in contact, the latter is highly indurated and pene- 
trated by siliceous matter. 
Dec. 17.—Tiie President in the Chair, 
Hutches Trower, Esq. of Upper Harley-Street, was 
elected a Member of the Society. 
The continuation of Mr. Webster’s paper on the upper 
strata of the S. E. part of England, was read. 
This part of Mr. Webster’s paper begins by a description 
of the marine deposit which covers the lower fresh-water 
formation ‘in the Isle of Wight. The place where it may 
be studied to most advantage i is Henden near Alum Bay. 
It here appears about half-way up the cliff, is about 36 feet 
thick, and dips a few degrees to the north. The substance | 
composing the principal part of the bed is a pale greenish 
marl, filled with shells chiefly cerithia, cytherez, and oysters, 
in a very perfect state of preservation. The extensive 
stratum containing shells, which appears at Woolwich and 
in many other parts of the London basin S. of the Thames, 
are also considered by Mr.Webster as portions of the upper 
marine formation. Beds containing similar fossils occur in 
the Paris basin, covering the gypsum and gypseous marls 
of the lower fresh-water formation. ¢ 
The above strata in the Paris basin are covered by very 
extensiye and thick beds of a pure sand, sometimes loose 
Hhe sometimes 
