$24 Geological Society. 
water thus descending through crevices being converted into va- 
pour in subterranean hollows, and then carried off in other direc- 
tions in the form of stufas or hot springs. I forbear to enlarge on this 
subject at present, as a description of the facts drawn up by Mr. Mar- 
tin before Mr. Strickland’s visit, will shortly be read to the Society. 
We have received from Capt. Belcher a suite of geological spe- 
cimens from various parts of the west coast of Africa, with remarks 
on the reefs and sand-banks of that coast; and a collection from the 
Rev. W. Hennah of recent calcareous limestone and volcanic pro- 
ducts from the island of Ascension. 
I shall next consider some papers relating more or less exclusively 
to fossil zoology, which have been read at our meetings during the 
last session. We are indebted to Mr. Broderip for a description of 
some new species of fossil Crustacea and Echinodermata, which were 
discovered by Lord Cole and Sir P. Egerton in the lias of Lyme 
Regis. One of these crustaceans belongs to a genus intermediate 
between the Palinurus and the Shrimp. It is of a gigantic size 
compared to any recent species, and belongs to a division of which 
the living types have been only met with in the arctic regions. 
Sir P. Egerton has described some peculiarities of structure in 
the occipital bone of an Ichthyosaurus, observed in the skeleton of 
a new and gigantic species recently discovered by Miss Anning at 
Lyme Regis. He also states that the axis and atlas in this genus 
are usually found adhering firmly together, and they are connected 
by an auxiliary bone, showing that strength rather than freedom of 
lateral motion was required in the neck of these animals. These 
observations have been confirmed by Mr. Owen and Mr. Clift. 
It has often been a question whether the bones of birds had ever 
occurred in strata below the chalk, some of the thin fragile bones 
found at Stonesfield, and formerly considered to be those of birds, 
having been ascertained to belong to Pterodactyls. In order to 
elucidate this point, Mr. Mantell lately placed all his specimens from 
the Wealden, supposed to be those of certain Grallz, or waders, in 
the hands of Mr. Owen, and the result of his examination has con- 
firmed Cuvier’s opinion that they are true ornitholites. They seem, 
therefore, to be the oldest authenticated fossils of this class hitherto 
found in Great Britain. The rarity of such remains in geological 
formations, especially in the marine, cannot surprise us; for in the 
recent shell marl of Scotland, formed in lakes much frequented by 
water-fowl up to the moment of their drainage, no bones of birds 
have as yet been detected amongst the numerous relics of deer, ox, 
pig, and other quadrupeds occurring in the marl. 
Mr. Darwin, in his travels in South America before alluded to, 
found, in crossing the continent from the Rio Negro to Buenos 
Ayres, many large bones of Mastodons, and other remains of the 
Mastodon at Port St. Julian, 50° S, lat., at a distance of more 
than six hundred miles from the former. He also saw, in the 
gravel of Patagonia, many bones of the Megatherium, and among 
the remains of five or six species of quadrupeds associated with them, 
he detected those of a species of Agouti. 
