EniTlSII ASSOCIATION MEETINfi. 
The Weil H'liir forminatcs in tlic Clioit Mclr'liir, a depression proljably 
cii^lif y IVct below tlie Mediterranean sea-level, and (he lowest point of the 
whole Sidiara. This basin extends eastwards to the Chott el Melah ( liake Tri- 
tonis), at a greater elevation, but yet scarcely rising to the sea-level, I'roni 
whieii it is separated by some thirty miles of sand-hills and rocks. 
Proceeding northwards of the Meh'hir, we rapidly lose all traces of the 
diliivian deposits, and come upon the chalk, chalk-marl, and greensand iu 
regular succession, dipping generally sonthwards. The three southerumosfc 
ridges of the Mons jVurcs, viz., the Ujcbel Cheeha, the Dj. Khaddoii, and 
Dj. Aniar, present us with these three stages of the cretaceous group in. 
order. 
When wc advance to the north of Biskra, the boundary between the Till and 
the eastern Sahara, the mountains are composed of masses of nuinnuilite lime- 
stone, with bands of gypsum and oecasioual irruptions of rock-salt, mixed with 
layers of marl. One of these mountains of rock-salt has been described long 
since by Dr. Shaw — that of El Outaia. 
There are many salt deposits, sometimes masses of isolated rock-salt, pei"- 
fectly pure, of many hundred yards in circumference, as at Hadjera el Mchl, 
(or Roehers de Sal), more frequently in the form of layers or incrustations on 
the plains near the Chotts, or beds of evaporated lakes. Some of the isolated 
rock-salt hills have been suggested to have been eruptions of argillaceous mud, 
gypsum, aud rock-salt across the secondary and tertiary deposits. 
In such a country as the Sahara, we cannot expect to find much mineral 
wealth, beyond the salt, gyjisum, aud natron. There is a quarry of oxide of 
manganese in the Djebel Trisgrariue, traces of lignite and carbonized trees at 
Ain el Ibel, and may hot springs — some pure, others strongly impregnated with 
chlorine. The temperature of oue of these I found to be one hundred aud 
twenty-five degrees Fahrenheit, of others from seventy-five to ninety-live degrees 
Fahrenheit. In one of the latter were swarms of a little fish, Cijpriiwdon 
diqmr, also found iu the warm springs of Egypt. 
ON THE INVERTEBRATE FAUNA OF THE LOWER OOLITES OF 
OXFORDSHIRE. 
By J. F. Whiteaves, F.G.S. 
The author remarked that, although the physical geology of the neighbour- 
hood of Oxford was, with some exceptions, tolerably well understood, eom- 
piU'atively little was known with respect to its palaeontology, especially that 
part relating to the invertebrate division of the animal kingdom. The only ex- 
ception he was aware of was a detailed list of the fossils of the Stonesfield 
slate in the volume of Oxford Essays for 1855, by Professor Phillips, and to 
this list the author was enabled to add twenty-seven species of shells, which he 
envnncratcd. 
Near the Kirtlingtou Station, on the Great Western Railway, several 
fine sections of the upper beds of the Great Oolite are remarkably well 
cxibited ; and in deep cuttings on the Oxford, Worcester, and Wolverhampton 
railway, between the Haudborough and Charllniry Stations, the lower beds of 
the same formation may be conveniently studied. The fossds procured from 
these beds, including the Stonesfield-slate, were one hundred and thirty-five 
species, of which oue hundred and twenty-eight were shells, four- echinodermata, 
three corals, and one Bryozoon. This list seemed to the author especially 
interesting, as tending to remove the isolation of the IMinehiuhamptou fauna, 
aud to prove that shells, &c,, previously detected only on the Cotswolds, were 
