26 



HARDWICKE'S SCIENCE-GOSSIP. 



striking fact — that the so-called " breaks " in the 

 continuity of organic remains are fast disappearing 

 before a more general geological investigation. The 

 Hallstadt and St. Cassian beds, occupying the bases 

 of the Austrian Alps, were formed along a sea- 

 bottom during later Triassic times, where the fauna 

 of the old and newer worlds met and commingled 

 as on a common platform. 



But it is to the third division of this interesting 

 formation that I must specially allude. The middle 

 member, the " Muschelkalk," is absent in England, 

 so that the Keuper beds are seen in many places in 

 midland and northern England reposing directly 

 upon the Bunter. Where this occurs there is usually 

 an " unconformability " between the two. That is 

 to say, the dip of the two sets of strata is different. 

 This means that the lower had been elevated before 

 the upper had deen deposited, and therefore indi- 

 cates a break in time between the two, and shows 

 us plainly they were not continuously deposited. 



The Keuper beds are my home. Here was I 

 bred and born ! From the top to the bottom, you 

 have ample evidence of the physical circumstances 

 under which they were deposited. Every layer in- 

 dicates shallow water; in the ripple-marks, sun- 

 cracks, rain-drop pittings, and feet-impressions of 

 extinct reptiles. In Cheshire this series contains 

 beds of rock-salt and gypsum, the whole attaining 

 a thickness of fifteen hundred feet. The beds of rock- 

 salt of which I am a humble portion, frequently 

 attain the thickness of a hundred feet ; and the 

 area, in Cheshire and elsewhere, over which these 

 extend, is calculated to be above one hundred and 

 fifty miles across ! This represents the magnitude 

 of the natural salt-pan where I was formed. The 

 beds are usually split up by a layer of clay or marl, 

 and the rock-salt masses are usually tinted with a 

 dirty red, caused by the slight admixture of iron. 

 But not a trace of a fossil or any other organic 

 remain do you ever get in the neighbourhood of the 

 salt-bearing beds ! Farther away, on what would 

 be the flat shores of the sea where the salt was 

 precipitated, you get evidences of fish and reptile 

 life; as in Shropshire, Cheshire, Leicestershire, 

 Warwickshire, &c. Mechanical impressions, such 

 as ripple-marks and sun-cracks, are plentiful enough 

 in the true salt-bearing series; but no vital evi- 

 dences ! 



What does this general absence of fossils mean ? 

 It is not that they could not be preserved, for you 

 have seen that other impressions are well enough and 

 accurately enough laid by. It must mean that, in 

 such limited areas at least, life from some cause or 

 another was excluded. Such was actually the case. 

 The shallow sea was so salt that no animal life 

 could exist therein. You have similar conditions 

 now in existence. The Dead Sea, extensive though 

 it is, has no fauna. Its waters are thoroughly 

 desolate, and know nothing of the pleasures of life. 



They are nothing but a vast menstruum, in which 

 chemical solutions are so thick, that precipitations 

 of the surcharges are constantly occurring. The 

 Dead Sea level is nearly a quarter of a mile below 

 that of the Mediterranean, and I am told that the 

 neighbourhood is marked by Dead Sea beaches, 

 indicating that the waters have been shrinking for 

 generations bygone. The river Jordan continues to 

 pour in his waters, which waters are more or less 

 charged with mineral matter held in solution. 

 The Jordan waters, however, are all evaporated 

 from the Dead Sea surface, and, as the mineral 

 matter cannot be disposed of in the same way, 

 there is no alternative except precipitation. This 

 is actually going on, and I am told that solid, cubic 

 crystals of pure salt may be dredged from the Dead 

 Sea bottom. 



As well as I can remember, the physical condi- 

 tions of the Keuper sea — at least over part of the 

 Cheshire area — very much resembled those now in 

 action in Palestine. The shells and thin flagstones 

 of the Keuper elsewhere are frequently marked by 

 the cubic pseudomorphs of salt, indicating that, far 

 away from where the salt was most rapidly forming, 

 the water was supersaturated. The absence of 

 molluscan and fish life in the Dead Sea will enable 

 you to understand the reason why the Cheshire salt- 

 bearing beds contain no fossils, although they are 

 so thickly crowded with evidences of ordinary 

 atmospherical and mechanical action. When these 

 beds were deposited, a Dead Sea existed in Che- 

 shire and Worcestershire, and for so long a period 

 that these thick, massive beds of rock-salt were 

 formed along its bottom by the simple action of 

 precipitation. We may regard these massive beds, 

 therefore, as locally representing the excess of salt 

 — just as iron-stone bands represent the excess of 

 iron, and coal-seams the excess of carbon. The only 

 difficulty which appears is the comparative purity of 

 the rock-salt layers, and this the element of time 

 sufficiently explains. It is very evident that the 

 physical conditions remained unchanged for a long 

 time, otherwise the rock-salt would have been inter- 

 calated with layers of other material. The stratum 

 of shell or marl which separates the two main beds 

 indicates a temporary suspension of these circum- 

 stances, after which the older conditions returned 

 and lasted until an entire change had set in. These 

 salt-masses are more or less rudely crystallized into 

 columns, but I believe this was a subsequent process 

 to the formation of the salt itself. Of course the 

 lime-springs, from which so much of the salt of com- 

 merce is now extracted, have been formed simply by 

 the surface water percolating the beds, and dissolv- 

 ing some of the solid salt in its course. At its exit, 

 at a distance from the rock-salt masses, it is then 

 charged with this culinary mineral. In many parts 

 of Cheshire the surface is doited with " meres," or 

 fresh-water lakes, the haunts of rare birds and plants, 



