Augiist 26, 1880] 



NAJURE^' 



387 



and Triassic epochs. On the contrary, it seems to me more 

 rational to attribute the poverty of the faunas of these epochs 

 to accidental abnormal conditions in certain areas, that for a 

 time partially disappeared during the deposition of the conti- 

 nental Muschelkalk which is absent in the British Triassic 

 series. 



In the whole of the Russian Permian strata only fifty-three 

 species were known at the time of the publication of "Russia 

 and the Ural Mountains," and I have not heard that this scanty 

 list has been subsequently increased. I am therefore inclined 

 to believe that the red marls, grits, sandstones, conglomerates, 

 and great masses of gypsum and rock-salt were all formed in a 

 flat inland area which was occasionally liable to be invaded by 

 the sea during intermittent intervals of minor depression, some- 

 times in one area, sometimes in another, and the fauna small in 

 size and poor in numbers is one of the results, while the depo- 

 .■■ition of beds of salt and gypsum is another. If fo, then in 

 the area now called Russia, in sheets of inland Permian water, 

 deposits were formed strictly analogous to those of Central 

 Europe and of Britain, but on a larger scale. 



Other deposits of salt deep beneath overlying younger strata 

 are stated to occur at Bromberg in Prussia, and many more 

 might be named as lying in the same formation in Northern 

 Germany. 



If we now tarn to the Triassic series it ii known that it con- 

 sists of only two chief members in Britain, the Eunter Sand- 

 stones and the Keuper or New Red Marls, the Muschelkalk of 

 the Continent being absent in our islands. No salt is found in 

 the Bunter Sandstones of England, but it occurs in these strata 

 at Schoningen in Brunswick, and also near Hanover. In the 

 low er part of the Keuper series deposits of rock-salt are com- 

 mon in England and Ireland. At Almersleben, near Calbe, 

 rock-salt is found in the Muschelkalk, and also at Erfurt and 

 Slottenheim in Thuringia and at WilhelmsgUick in Wlirtemburg. 

 In other Triassic areas it is known at Honigsen, Hanover, in 

 middle Keuper beds. In the red shales at Sperenbergand Lieth 

 on the Lower Elbe, salt was found at the depth of 3,000 feet, 

 and at Stassfurth the salt is said to be "several hundred yards 

 thick."' 



In Central Spain rock-salt is known, and at Tarragona, Taen, 

 and also at Santander in the north of Spain, all in Triassic 

 strata. Other localities may be named in the Upper Trias, such 

 as the Salzkammergut, Aussee, Hallstatt, Ischl, Hallein in 

 Salzburg, Halle in the Tyrol, and Berch.esgaden in Bavaria. 



In the Salt Range of mountains in Northern India saliferous 

 strata are refen-ed with some doubt by Medlicott and Blanford 

 to the Triassic strata. 



In the Jurassic series (Lias and Oolites) salt and gypsum are 

 not uncommon. One well-known instance occurs at Berg in the 

 valley of the Rhone in Switzerland, where salt is derived from 

 the Lias. Salt and gypsum are also found in Jurassic rocks at 

 Burgos in Spain. At Gap in France there is gypsum, and salt 

 is found in the Austrian Alps in Oolitic limestone. 



In the Cretaceous rocks salt occurs, according to Lartet, at 

 Jebel Usdom by the Dead Sea, and other authorities state that 

 it occurs in the Pyrenees and at Biskra in Africa, where " moun- 

 tains of salt " are mentioned as of Cretaceous age. The two 

 last-named localities are possibly uncertain ; but whether or not 

 this is the case, it is not the less certain that salt has been 

 deposited in Cretaceous rocks, and, judging by analogy, probably 

 in inland areas of that epoch. 



In the Eocene or Older Tertiary formations, rock-salt is found 

 at Cardona in Spain, and at Kohat in the Punjab it occurs at 

 the base of Nummulitic beds. It is also known at Mandi in 

 India in strata supposed to be of Nummulitic Eocene age. 



The record does not end here, for a zone of rock-salt lies in 

 Sicily at the top of the Salina clays in Lower Miocene beds, and in 

 Miocene strata gypsum is found at several places in Spain, while 

 salt also occurs in beds that are doubtfully of Miocene age (but 

 may be later) at Wielitzka in Poland, Kalusz in Galicia, 

 Bukowina, and also in Transylvania. 



In Pliocene or Later Tertiary formations, thick beds of 

 gypsum are known in Zante, and strata of salt occur in 

 Roumania .and Galicia, while in Pliocene rocks, according to 

 Dana, or in Post-Tertiary beds, according to others, a thick bed 

 of pure salt was penetrated to a depth of 3S feet at Petit Anse 

 in Louisiana. This ends my list, though I have no doubt that, 

 by further research, many more localities might be given. 

 Enough, however, has been done to show that rock-salt (and 

 other salts) are of frequent recurrence throughout all geological 



time, and as in my opinion it is impossible that common salt can 

 be deposited in the open ocean, it follows that this and other 

 salts must have been precipitated from solutions, which, by the 

 effect of solar evaporation, became at length supersaturated, like 

 those of the Dead Sea, the great salt lake of Utah, and in other 

 places which it is superfluous to name. 



Fresh-ivatir, Lakes and Estuaries. — I now come to the 

 subject of recurrences of fresh- water conditions both in lakes and 

 estuaries. In the introduction to the "Geology of India," by 

 Messrs. Medlicott and Blanford, mention is made of the Blaini 

 and Krol rocks as probably occupying "hollows formed by 

 denudation in the old gneissic rocks," and the inference is drawn 

 that "if this be a correct view, it is probable that the cis- 

 Himalayan Paleozoic rocks are in great part of fresh-water 

 origin, and that the present crystalline axis of the Western 

 Himalayas approximately coincides with the shore of the ancient 

 Palaeozoic continent, of which the Indian peninsula formed a 

 portion." The Krol rocks are classed broadly with "Permian 

 and Carboniferous " deposits, but the Blaini beds are doubtfully 

 considered to belong to Upper Silurian strata. If this point be 

 by and by established, this is the earliest known occurrence 

 of fresh-water strata in any of the more ancient Palaeozoic 

 formations. 



It is a fact worthy of notice that the colour of the strata 

 formed in old lakes (whether fresh or salt) of Palaeozoic and 

 Mesozoic age is apt to be red : a circumstance due to the fact 

 that each little grain of sand or mud is usually coated with a 

 very thin pellicle of peroxide of iron. Whether or not the 

 red and purple Cambrian rocks ' may not be partly of fresh- 

 water origin, is a question that I think no one but myself has 

 raised.^ 



There is however, in my opinion, no doubt with regard to 

 the fresh-water origin of the Old Red Sandstone, as distinct from 

 the contemporaneous marine deposits of the Devonian strata. 

 This idea was first started by that distinguished geologist, Dr. 

 rieining, of Edinburgh, followed by Mr. Godwin-Austen, who, 

 from the absence of marine shells and the nature of the fossil 

 fishes in these strata, inferred that they were deposited, not in 

 the sea, as had always been asserted, but in a great fresh-water 

 lake or in a series of lakes. In this opinion I have for many 

 years agreed, for the nearest analogies of the fish are, according 

 to Huxley, the Polypterus of African rivers, the Ceratodus of 

 Australia, and in less degree the Lepidosteus of North 

 America. The truth of the supposition that the Old Red 

 Sandstone was deposited in fresh water, is further borne out by 

 the occurrence of a fresh-water shell, AnoJonta jiil-esii, and of 

 ferns in the Upper Old Red Sandstone in Ireland ; and the same 

 shell is found at Dura Den in Scotland, while in Caithness, 

 along with numerous fishes, there occurs the small bivalve 

 crustacean Esthcria tnurchisoniiv. 



I think it more than probable that the red series of rocks that 

 form the Catskill Mountains of North America (and with which 

 I am personally acquainted) were formed in the same manner as 

 the Old Red Sandstones of Britain ; for, excepting in one or two 

 minor interstratifications, they contain no relics of marine life, 

 while "the fo;sil fishes of the Catskill beds, according to Dr. 

 Newberry, appear to represent closely those of the British Old 

 Red Sandstone" (Dana). 



The Devonian rocks of Russia, according to the late Sir 

 Roderick Murchison, consist of two distinct types, viz., 

 Devonian strata identical in general character with those in 

 Devonshire and in various parts of the continent of Europe. 

 These are exclusively of a marine character, while the remainder 

 corresponds to the Old Red Sandstone of Wales, England, and 

 Scotland. 



At Tchudora, about 105 miles south-east of St. Petersburg, 

 the lowest members of the series consist of flag-like, compact 

 lime- tones accumulated in a tranquil sea, and containing fucoids 

 and encrinites, together with shells of Devonian age, such as 

 Spirifers, Terebratula\ Orthis, Leptxnas, Avicula, Modiola, 

 Natica, Bellerophon, &c., while the upper division graduates 

 into the Carboniferous series as it often does in Britain, and, like 

 the Old Red Sandstone of Scotland, contains only fish-remains, 

 and in both countries they are of the same species. " Proceed- 

 ing from the Valdai Hills on the north," the geologist "quits a 

 Dezwiian Zone with a true ' 01 J Red' type dipping under the 



■ By Cambrian. I mean only the red and furflc rocks of Wales, England, 

 SC' tiand, and Ireland, older than the Mcnevian beds, or any later division 

 of the Silurian strata that may chance to rest upon them. 



= '■ On the Red Rocks of England of older date than the Trias." Jour. 

 Cvl. Sue, 1871, vol. xxviii. 



