SCIENTIFIC SUMMAKY. 
107 
is present in sucli a great proportion in many rocks, would decompose the 
carbonates and sulphates, and, aided by the presence of water, the chlorids 
both of the rocky strata and of the sea ; while the organic matters and the 
fossil carbon would be burned by the atmospheric oxygen. From these 
re-actions would result a fused mass of silicates of alumina, alkalies, lime, 
magnesia, iron-oxyd, &c. ; while all the carbon, sulphur, and chlorine, in the 
form of acid gases, mixed with watery vapour, nitrogen, and a probable 
excess of oxygen, would form an exceedingly dense atmosphere. When the 
cooling permitted condensation, an acid rain would fall upon the heated 
surface of the earth, decomposing the silicates, and giving rise to chlorids 
and sulphates of the various bases, while the separated silica might take the 
form of crystalline quartz. In the next stage of the process, the portions of 
the primitive crust not covered by the ocean would undergo a decomposition 
under the influence of hot moist atmosphere charged with carbonic acid, and 
the felspathic silicates become converted into clay, with separation of the alkali. 
This, absorbing carbonic acid from the atmosphere, would find its way to 
the sea, where, having first precipitated from its highly-heated waters various 
metallic bases then held in solution, it would decompose the chlorid of 
calcium, giving rise to chlorid of sodium on the one hand, and to carbonate 
of lime on the other. In this way we obtain a notion of the processes by 
which from a primitive fused mass may be generated the siliceous, calcareous, 
and argillaceous rocks which make up the greater part of the earth’s crust ; 
and we also understand the source of the salts of the ocean. — Vide Canadian 
Naturalist , vol. II. note 4. 
The Green Marble of Connemara. — Professor Harkness, of Queen’s College, 
Cork, communicated his observations on these rocks to the British 
Association, at its last meeting. A series of sections and maps, which he 
-displayed, proved that the green marbles of Connemara are a local and 
peculiar development of light-grey subcrystalline limestone, which lies on the 
north side of the gneiss rocks of the south of the Bens of Connemara. This 
limestone dips conformably under these gneissic rocks. It is superposed con- 
formably on quartz rocks, and these quartz rocks, with their superposed deposits, 
-are thrown into numerous contortions in the Connemara country. Where they 
are most curtailed, the limestones have opened out in their lines of lamination, 
and into these openings the serpentinous matter, to which the green marble owes 
its colour, has been introduced. The metamorphic strata in the Connemara 
country appertain to the Lower Silurians. They are the equivalents of the 
Quartz rocks, Upper Limestone, and Upper Gneiss of the Highlands of Scot- 
land, described by Sir R. I. Murchison. It has been stated that Eozoon 
Canadense occurs among the green marbles of Connemara. The structure 
which has given rise to this opinion is purely mineral, and has resulted from 
the deposition of Serpentine upon Tremolite and asbestiform minerals. 
The Loiver Lias of Somerset. — In a paper read before the Geological 
Society (Dec. 6th), the Rev. P. B. Brodie described a section recently 
exposed at Milton Lane, one mile and a half north of Wells, which exhibited 
the Lima-beds passing into and overlying the White Lias- and Avicula-con- 
torta zone. The author described the section (which was constructed by Mr. 
-J. Parker and himself) in detail, and showed that the Lima series attained 
here a thickness of 10 feet 4 inches, and the Rhcetic bads, including the grey 
