292 Astronomical Society. 
that it owes its origin, in this part of England, to causes much 
more local in their operation than those generally assigned. 
He examines how far the phenomena attending its distribu- 
tion are consistent with the supposition, that the diluvium was 
formed in consequence of the protrusion of the inferior through 
the superior strata, along the anticlinal axis which now sepa- 
rates the tertiary basins of London and Hampshire. Admit~ 
ting that this elevation took place when all the strata were be- 
neath the level of the sea, Mr. Lyell endeavours to show, that 
the returning waters, when the land was raised to its present 
position above the sea, would have strewed the debris of the 
older over the newer formations, as we now find it; while those 
of the more recent would not cover, except in inconsiderable 
quantities, the more ancient strata; and that the marked dis- 
similarity between the diluvium of the Wealds of Kent and 
Sussex, and that of Hampshire and the neighbourhood of 
London, may thus be accounted for. As the freshwater for- 
mations in Hampshire and the Isle of Wight, as well as the 
Plastic and London clays, are covered by deep beds of a simi- 
lar gravel, consisting of chalk-flints, the author states several 
geological facts to prove, that these more recent formations 
existed when the chalk and tertiary strata were elevated, and 
notwithstanding their difference of inclination, even when the 
strata of Alum-bay assumed their vertical position; and con- 
sequently they were all covered indiscriminately by a similar 
stratum of diluvium. 
April 7.—A translation was read of a letter from M. de Gim- 
bernat, of Geneva, principally upon sulphate of soda, to G. B. 
Greenough, Esq. F.G.S. &c. 
A paper, entitled, “ On the geology of the valley of the St. 
Laurence ;” by John J. Bigsby, M.G. F'.G.S. was read in part. 
April 21.—The reading of Dr. Bigsby’s paper was continued. 
ASTRONOMICAL SOCIETY. 
March 10.—A paper was read “ On an appearance hitherto 
unnoticed in the nebula of Orion,” communicated by the Astro- 
nomer Royal. ‘This appearance was detected by means of 
Mr. Ramage’s 25-feet reflector, which is now placed up at the 
Royal Observatory. It is well known that among a variety 
of stars, which appear at the same time in the field of view of 
the telescope with this nebula, there are four very bright ones, 
which form a trapezium, and, at a little distance, three others 
nearly in a straight line. These three stars, Mr. Pond observes, 
are neithe: situated on the edge of the nebula, nor are they pa- 
rallel to the edge; but they seem to be insulated from the ne- 
bula, the light of which retires from them in a semicircular 
form, 
