British Association for the Advancement of Science. 271 
matter. ‘Through this quarry, a trap dyke passes, altering the rocks 
on each side. A specimen of the metamorphic rock encrusted by 
chabasie was exhibited. The general appearance of the quarry led 
Mr. Yates to the conclusion that there bad been a deposit formed 
by a current near the shore of a sea, which deposit had been fixed 
in a bay or recess where the remains of vegetables lay without being 
disturbed ; and he alluded to the banks at Liverpool, where scarce 
any drifted plants had been discovered, owing to the continued mo- 
tion of the currents, while they might be found in coves along the 
shores where the water was less agitated. 
Impressions in sandstone.—The Rev. Mr. Clarke exhibited speci- 
mens of vegetable remains inclosed in new red sandstone from Amer- 
ica transmitted to him by Prof. Hitchcock, who discovered the 
marks of the steps of birds in this rock a short time since. In a Jet- 
ter to Mr. Clarke, the Prof. has notified further discoveries of these 
singular steps, and also the remains of Saurians in this formation. 
In graywacke he had also discovered the remains of Marsupial quad- 
rupeds. 
Argas Persicus—W. S. Macleay in the chair.—Dr. Traill ex- 
hibited a specimen of the Argas Persicus, or poisonous bug of Mi- 
anneh in Persia, giving a short notice of its effects. In some parts 
of Persia it is the prevalent belief that this animal not only produces 
fever, but often deaih from its bite. It is not a true insect, but be- 
longs to the order Arachnide, and to the genus Argas, from which 
it was separated by Lamarck. Two districts in Persia are largely 
infested with it, and it is eapotitie that to aor axpeers in these is 
certain death. 
Dr. Bell, a resident, had never known a case in which death was 
produced, but had seen persons extremely ill from its effects.—The 
Chairman doubted whether there was sufficient authority to believe 
that the bite of the insect was mortal, and ascribed the dangerous ef- 
fects to be the inflammation produced by pulling out a serrated probo- 
scis, and stated his opinion that death would not be produced unless 
in a diseased and excitable habit of body.—Dr. Traill stated, that its 
fatal effects had been positively mentioned by Sir R. K. Porter, Mr. 
Morier and other travellers. During the time that Gen. White was 
envoy to the Persian Court, the Schah dispatched a messenger after 
him, who requested him not to pitch his tent on a certain part near 
the city, on account of the bites of the insects—Rev. Mr. Hope 
yeferred toa similar species in St. Domingo, which attack horses 
