418 
NATURE 
[March 23, 1871 

in mind that, from the continual action of denudation, the ex- 
isting sedimentary rocks only represent a fraction of the whole 
thickness of sediments that have been deposited. Taking the 
denudation of the area of the Mississippi as a guide, he estimates 
the wearing down of the land at one foot in 6,000 years, and 
the matter thus removed spread over the bottom of the ocean 
would produce a deposit one foot thick in 14,400 years. Taking 
the maximum thickness of British sedimentary strata as cal- 
culated by Prof. Ramsay, namely, 72,000 feet, to represent the 
mean thickness of all the sedimentary rocks which ever have 
been formed, the author thus gets 1,036,800,000 years as the 
age of the stratified rocks. Mr. Croll also notices the conditions 
of the deposition of the sediment carried from the land, and 
his remarks upon this subject are all worthy of consideration. 
The editor, Mr. H. Woodward, describes and figures a new 
Myriopod from the Scotch coal-measures, under the name of 
Euphoberia Brownii, and also some new palzeozoic Phyllopod 
Crustacea, namely Ceratiocaris ludensis, a gigantic species from 
the Lower Ludlow of Leintwardine, C. ovetonensis and C. trun- 
calus, from the yellow carboniferous limestone of Oreton and 
Farlow in Worcestershire, and Drthvrocaris Belli, from the 
Middle Devonian of Gaspé. He-also figures a specimen of D. 
tenuistriatus, McCoy. Mr. De Rance communicates a paper on 
the occurrence of two distinct glaciations inthe Lake District ; 
Mr. John A itken notices some curious faults occurring in drift at 
Stockport in Cheshire; and Mr, S. C. Perceval describes the 
occurrence of Websterite at Brighton. 


SOCIETIES AND ACADEMIES 
LonDON 
Royal Society, March 16.—*‘ Description of Ceraéodus, a genus 
of Ganoid Fishes recently discovered in rivers of Queensland, 
Australia.” By Dr. Albert Giinther, F.R.S. 
to this communication. —“ On the Formation of some of the 
Subaxial Arches in Man.” By George W. Callender. 
Geological Society, March 8.—Mr. Joseph Prestwich, 
F.R.S., president, in the chair. 
vost and Mr. John Haines were elected Fellows of the Society ; 
and Dr. C. Nilsson, was elected a foreign member of the 
Society. The following communication was read :—(I) ‘‘On 
the Red Rocks of England of older date than the Trias,” by 
Prof. A. C, Ramsay, LL.D., F.R.S., V.P.G.S. The author 
stated that the red colour of the Triassic beds is due to peroxide 
of iron, which encrusts the sedimentary grains as a thin pellicle. 
This could not have been deposited in an open sea, but rather in 
an inland salt lake or lakes. ‘The peroxide of iron, which stains 
the Permian, Old Red Sandstone and Cambrian rocks, is be- 
lieved by the author to have been deposited in the same manner, 
in inland waters, salt or fresh. Agreeing with Mr. Godwin- 
Austen, the Old Ked Sandstone was of Lacustrine origin. The 
absence of marine shells helps to this conclusion. 
do not contradict it, for some of their nearest living con- 
geners live in African and American rivers. The life of the 
Upper Silurian deposits of Wales and the adjoining districts 
continued in full force up to the passage-beds, which mark 
the change from Silurian to Old Ked Sandstone. In these tran- 
sition strata, genera, species, and individuals are often few, and 
dwarfed in form. Near Ludlow and May Hill the uppermost 
Silurian strata contain seeds and fragments of land plants, 
indicating the neighbourhood of land, and the poverty of 
numbers and the small size of the shells a change in the condi- | 
tion of the waters. The fish of the Old Red Sandstone also 
indicate a change of condition of a geographical kind. 
circumstances which mark the passage of Silurian into Old Red 
Sandstone were as follows :—First, shallowing of the sea, so 
that the area changed into fresh and brackish lagoons, afterwards 
converted into great freshwater lakes. 
as for example in the Swedish lakes. The same may 
have been the case in the Old Red Sandstone period. 
The Old Red Sandstone waters at their beginning are comparable 
to the Black Sea, now steadily freshening ; or the Caspian, once 
united to the North Sea, if by a change of amount of rainfall and 
evaporation it freshened by degrees, and finally became a fresh- 
water lake, The Permian strata, to a great extent, consist of 
red sandstones and marls in the greater part of England ; and 
the Magnesian Limestone of the north of England is also in less 
We shall return | 
Lieut. Lewis de Teissier Pre- | 
The fish | 
At the present day | 
marine species are occasionally found living in fresh water, | 

The 

degree associated with red marls. These do not occur in the 
same districts of England, excepting in Lancashire, where a few 
beds of Maynesian Limestone are interstratified withthe marls. The 
sandstones and marls being red, the colouring matter is considered 
to be due to peroxide of iron, possibly precipitated from carbonate 
of iron, introduced in solution into the waters. Land plants are 
found in some of the Permian beds, showing the neighbourhood 
of land. No mollusca are found in most of the red beds, except 
a brachiopod in Warwickshire, and a few other genera in Lan- 
cashire, in marls associated with thin bands of Magnesian Lime- 
stone. The traces of amphibians are like those found in the 
Keuper Sandstone, viz., Dasyceps Bucklanai and lalsyrinthodont 
footprints in the Vale of Eden and at Corncockle Moor, printed 
on damp surfaces, dried in the sun, and afterwards flooded ina 
way common in salt Jakes. Pseudomorphus crystals of salt and 
gypsum help to this conclusion. The molluscous fauna of Lan- 
cashire, small in number, in this respect resembles the fauna of 
the Caspian Sea. The fauna of the Magnesian Limestone of 
the east of England is more numerous, comprising thirty-five 
genera and seventy-six species, but wonderfully restricted when 
compared with the Carboniferous fauna, The specimens are 
generally dwarfed in aspect, and in their poverty may be com- 
pared to the Caspian fauna of the present day. Some of the fish 
of the Marl-Slate have strong affinities to carboniferous genera, 
which may be supposed to have lived in shallow lagoons, 
bordered by peaty flats; and the reptiles lately described by 
Messrs. Howse and Hancock have terrestrial affinities. Besides 
the poorness of the Mollusca, the Magnesian Limestone seems 
to afford other hints that it was deposited in an inland salt lake 
subject to evaporation. Gypsum is common in the interstratified 
marls. In the open sea limestone is only formed by organic 
agency, for lime, in solution, only exists in small quantities in 
such a bulk of water ; but in the inland salt lakes carbonates of 
lime and magnesia might have been deposited simultaneously by 
concentration of solutions due to evaporation. Some of the 
Magnesian Limestone strata have almost a tufaceous or stalag- 
mitic aspect, as if deposited from solution. The Cambrian strata 
also show some evidence of not being true marine deposits. 
They are purple and red, like the other strata previously spoken 
of ; and the surfaces of the beds sometimes exhibit sun-cracks 
and rain-pittings. The trilobite Palcopyge Ramsayi is con- 
sidered by the author to be an accidental marking, simulating 
the form of a trilobite ; and the fossils of St. David’s are found 
in grey beds, which may mark occasional influxes of the sea, due 
to oscillations of level. - The foregoing reasonings, in the author's 
opinion, lead to the conclusion that a continental area existed 
more or less in the northern hemisphere from the close of the 
Silurian to the end of the Triassic epoch, and that this geographi- 
cal continuity of land implies probable continuity of continental 
genera. There is therefore no palzontological reason why the 
Hyperodapedon, Telerfeton, and Stagonolepis of the Elgin country 
should be considered of Triassic age, especially as the beds in 
which they occur are stratigraphically inseparable from the Old 
Red Sandstone. Finally, terrestrial and marine European epochs 
were rapidly reviewed. 1. The Cambrian epoch was probably 
fresh water. 2. The Old Red Sandstone, Carboniferous, Permian, 
and Trias were formed during one long continental epoch. This 
was brought to an end by partial submergence during the Jurassic 
epoch ; and by degrees a new continental area arose, drained by 
the great continental rivers of the Purbeck and Wealden series, 
as shown in various parts of Europe. 3. This continent was 
almost entirely swallowed up in the Upper Cretaceous seas. 
4. By subsequent elevation the Eocene lands were formed, 
and with this continent there came in a new terrestrial fauna. 
Most of the northern half of Europe since then has been 
continental, and its terrestrial fauna essentially of modern type. 
If according to ordinary methods we were to classify the old 
terrestrial faunas of North America, Europe, Asia, and probably 
of Africa, a Palzeozoic epoch would extend from Old Red Sand- 
stone to Wealden times, and a Neozoic epoch at least from the 
Eocene period to the present day. The Upper Cretaceous 
strata would at present remain unclassified. The marine epoch 
would also temporarily be dividel into two, Paleozoic from 
Laurentian to the close of the Permian times, and all besides 
down to the present day, would form a Neozoic series. The 
generic gaps between the two begin already to be filled up. The 
terrestrial and the marine seri»s at their edges at preseni overlap 
each other. The great life-gaps between the two terrestrial 
periods may some day be filled up by the discovery of the traces 
of old continents containing intermediate developments of struc- 
ture as yet undiscovered. rof. Huxley was pleased to find that 
