Notice of a Fossil Nautilus froiyt the Isle of Sheppy. 105 
interstratified layers of concretionary nodules, commonly 
called septaria or cement stones. This clay belonged to the 
lower tertiary formation, and formed a part of the London 
basin — one of those isolated fluvio-marine deposits which took 
place in hollows of the chalk subsequent to the cretaceous 
epoch. On the north side of the island, and eastward from 
SheernesSj the cliffs rise to the height of from one to two 
hundred feet, and, chiefly from atmospherical causes, v^ere 
constantly crumbling down in large prismatic masses, which 
gradually broke up, and formed a flat shore of fine silt. Mud 
banks extended off shore for about half a milCs and at low 
water workmen were employed in procuring the cement stones. 
The beach was not more than from ten to twenty yards wide, 
on which were strewed abundance of fossil fruits, wood, Crus- 
tacea, and moliusca, which had fallen out of the clay. Dr 
M'Bain said, he had frequently obtained upwards of a hundred 
Eocene fossils in a single excursion, and that the remains of 
fish and reptilia were also of frequent occurrence in the Lon- 
don clay of the Island of Sheppy. He added, that many of 
these Eocene fossils became mixed with recent organisms, and 
were buried together in the re-composed silt, which the hasty 
generalization of some palseontologist, in a future new geolo- 
gical epoch, might consider as a sufficient proof that they also 
lived together at the same time iu the Cainozoic period. 
(2.) Notice of the Nucula decussata, /ouwcZ in the so-called Raised 8ea~ 
beach Bed at Leit'i. By Jamks M'Bon, M.D., R.N. 
The members of the Society, Dr M'Bain said, were no 
doubt familiar with a bed of sand and gravel extending along 
the shores of the Forth in a more or less continuous manner, 
and generally known as the raised sea-beach bed. This de- 
posit had been considered by several eminent geologists to re- 
present an ancient sea-beach, which, in consequence of a gene- 
ral elevation of the land, had been raised twenty feet or more 
above the level of the sea, at a comparatively recent geologi- 
cal period. This view was strenuously opposed by the late 
Professor John Fleming, who maintained that this so-called 
raised sea-beach bed and other accumulations of a similar 
VOL. II. 
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