70 Medico- Botanical Society of London. 
A paper was also read, entitled, A geological sketch of part 
of the West of Sussex, and the N.E. of Hants, &c., by R. J. 
Murchison, Esq. F.G.S. &c. 
In this memoir Mr. Murchison describes the geological 
relations, distribution, and characteristic fossils of the strata of. 
that part of the west of Sussex which is bounded on the south 
by the chalk escarpment of the South Downs, and that part 
of: Hampshire which is included by the Alton chalk hills. 
These strata, commencing below the chalk, in a descending 
series, are, 1. Malm-rock, or upper green-sand.—2. Gault.— 
3. Ferruginous green-sand.—4. Weald clay. The Weald 
clay in the valley of Harting Combe may be regarded as the 
central nucleus of this district; mantling round which, and ex- 
tending up to either chalk range, the other formations are de- 
veloped in regular succession: the breadth and boundaries 
of each are laid down by the author on a coloured portion of 
the Ordnance Map, to which a section is annexed. 
The Malm-rock of Western Sussex is identical with the stone 
of Merstham: it is characterized by constituting terraces which 
afford a rich soil favourable to wheat. It sometimes furnishes 
a building-stone, contains occasionally a calcareous blue chert, 
and abounds in organic remains. 
The Gault of this district has been cut through to the depth 
of 120 feet, at Alice Holt, and iridescent Ammonites and other 
fossils are found in it. This clay is marked by fertile water- 
meadows ; and the timber, presenting a green belt, clearly dis- 
tinguishes it from the rich wheat land of the malm-rock above, 
and the arid expanse of the ferruginous green-sand below it. : 
Of this latter formation the upper beds consist of pure 
white sand, and in some places compact ironstone and. iron- 
stone in large cellular tubes are found in it. In the middle beds 
occurs a calcareo-siliceous grit, called Bargate-stone; in the 
lower, a siliceous yellow building-stone containing casts of Am- 
monites, Terebratule, &c.—The Weald clay includes in its 
middle beds the compact Petworth marble; and in lower beds 
of clayin which tabular calcareous grit occurs, Mr. Murchison 
has discovered, together with scattered shells of the Vivipara 
Fluviorum, the bones of a large unknown vertebrated animal, 
specimens and drawings of which accompany this memoir. 
Jan. 6, 1826.—The reading of Mr. De la Beche’s paper on 
the geology of Jamaica, was continued. 
MEDICO-BOTANICAL SOCIETY OF LONDON. 
On Monday the 16th Jan. this Society held its anniversary 
meeting, when the following Officers and Council, were elect- 
ed for the present year:—President, Sir James M‘Gregor, 
