FOSSIL FOOD.

New Zealand Mail, Issue 764, 22 October 1886, Page 9

FOSSIL FOOD.

Cornhiel Magazine.

There is something at first sight rather .ridiculous in the idea of eating a fossil. To be sure, when the frozen mammoths of Siberia were first discovered, though they had been dead for at least 80,090 years (according to Dr Cioll’s minimum reckoning for the end of the great ice age), and might therefore naturally have begun to get a little musty, they had nevertheless been kept so fresh that the wolves and bears greedily devoured the precious relics for which the naturalists of Europe would have been ready gladly to' pay the highest market price of be3t beefsteak. Furthermore, some of the bones of extinct animals found beneath the stalagmitic floor of caves, in England and elsewhere, presumably of about the same age as the Siberian mammoths, still contain enough animal matter to produce a good strong stock for antideluvian broth, which has been scientifically described by a high authority as pre-Adamite jelly. The con gress of naturalists at Tubingen a few years since had a smoking tureen of this cave-bone soup placed upon the dinner table at their hotel one evening, and pronounced it with geological enthusiasm ‘scarcely inferior to prime oxtail.’ There is one form of fossil food, however, which appears constantly upon all our tables at breakfast, lunch and dinner, every day, and which is so perfectly familiar to every one of us that we almost forget entirely its immensely remote geological°origin. The salt in our salt-cellars is a fossil product, laid down ages ago iu some primaeval Dead Sea or Caspian. , Since that thick bed of rock salt was first precipitated upon the dry floor of some old evaporated inland sea, the greater part of the geological history known to the world at large has slowly unrolled itself through incalculable ages. The way salt got originally deposited in these great rock beds is very well illustrated for us by the way it is still being deposited in the evaporating waters of many inland seas. For many age 3 the intermediate soil has been quite literally rising in the' world, but to this day a continuous chain of salt lakes and marshes runs between the Caspian and the Black Sea, and does its best to keep alive the memory of the time when they were both united in a single basin. All along this intervening tract, once sea but now°dry land, banks of shells belonging to kinds still living in the Caspian and Black Sea alike testify to the old line of water communication. One fine morning (date unknown) the intermediate belt began to rise up between them; the water was all pushed off into the Caspian, but the shells remained to tell the tale even unto this day. Now when a bit of the sea gets cut off in this way from the main ocean, evaporation of its waters generally takes place rather faster than the return supply of rain, rivers, and lesser tributaries. In other words, the inland sea or salt lake begins slowly to dry up. This is now just happening in the Caspian, which is in fact a big pool in course of being slowly evaporated. By-and bye a point is reached when the water can no longer hold in solution the amount of salts of various sorts that it originally contained. In the technical language of chemists and physicists, it begins to get supersaturated. Then the salts are thrown down as a sediment atthe bottom of the sea or lake, exactly as crust forms on the bottom of a kettle. Gypsum is the first material to be so thrown down ; because it is less soluble than common salt, and therefore sooner got rid of. It forms a thick bottom layer in the bed of all evaporating inland seas ; and as plaster of Paris it not only gives rise finally to artistic monstrosities hawked about the streets for the degradation of national taste, but also plays an important part in the manufacture of bonbons, the destruction of the human digestion, and the ultimate ruin of the dominant white European race. Only a third of the water in a salt lake need be evaporated before the gypsum .begins to be deposited in a solid layer over its whole bed ; it is not till 93 per cent of the water has gone, and only 7 per cent is left that common salt begins to be thrown down. When that point of intensity is reached, the salt, too, falls as a sediment to the bottom, and there overlies the gypsum deposit. Hence all the world over, wherever we come upon a bed of rock salt, it almost invariably lies upon a floor of solid gypsum. The Caspian, being: still a very respectably modern sea, constantly supplied with fresh water from the surrounding rivers, has not yet begun by any means to'Meposit salt on its bottom from its whole mass, but the shallow pools and long bays around its edge have crusts of beautiful rose colored salt-crystals forming upon their sides ; and as these lesser basins gradually dry up, the sand, blown before the •wind, slowly drifts over them, so as to form miniature rock-salt beds on a very small scale. The Great Salt Lake of Utah, sacred to the memory of Brigham Young, gives us an example of a modern saline sheet of very different origin, since it is in- fact not a branch of the sea at all, but a mere shrunken remnant of a very large freshwater-lake system, like that of the still-existing St. Lawrence chain. Once upon a time, American geologists say, a huge sheet of water, for which they have even invented a definite name, Lake Bonneville, occupied a far larger valley among the outliers of the

Rocky Mountains, measuring 300 miles in one direction by ISO miles in the ot.ier. Beside this primitive Superior lay a second great sheet —an early Huron—(Lake Lahontan, the geologists call it) almost as big, and equally of fresh water. By-and-by—the precise dates are necessarily indefinitesome change in the rainfall, unregistered by any contemporary New York Herald, made the waters of these big lakes shrink and evaporate. Lake Lahontan shrank away like Alice in Wonderland, till there was absolutely nothing left of it; Lake Bonneville shrank till it attained the diminished size of the existing Great _ Sa.t Lake. Terrace after terrace, running m long parallel lines on the sides of the Wahsatch Mountains around, mark the various levels at which it rested for awhile on its gradual downward course. It is still falling indeed ; and the plain around is being gradually iincovered, forming the white salt-encrusted shore with which all visitors to the Mormon city are so familiar. Our English salt supply is chiefly derived from the Cheshire and Worcestershire salt-regions, which are of triassic age. Many of the places at which the salt is mined have names ending in wich, Northwich, Middlewich, Nantwich, Droitwich, Netherwicb, aud Shirleywich. This termination wich is itself curiously significant, as Mr Isaac Taylor has shown, of the necessary connection between salt and the sea. The earliest known way of producing salt was of course in shallow pans on the sea-shore, at the bottom of a shoal bay, called in Norse and early English a wick or wich ; and the material so produced is still known in trade as bay salt. By and by, when people came to discover the inland brine pits and salt mines they transferred to them the familiar name, a wich ; and the place where the salt was manufactured came to be known as wych-houses. Droitwich, for example, was originally such a wich, where the droits or dues on salt were paid at the time when William the Conqueror s commissioners drew up their great survey for Domesday Book. A good-sized Caspian used to spread across the centre of England and north of Ireland in triassic times, bounded here and there, as well as Dr. Hull can make out, by the Welsh Mountains, the Cheviots, and the Donegal Hills, and with the Peak of Derbyshire and the Isle of Man standing out as separate islands from its blue expanse. Slowly, like most other inland seas, this early British Caspian began to lose weight and to shrivel away to ever smaller dimensions. In Devonshire, where it appears to have first dried up, we get no salt, but only red marl, with here and there a cubical cast, filling a hole once occupied by rocksalt, though the percolation of the rain has long since melted out that very soluble substance, aud replaced it by a mere mould in the characteristic square shape of salt crystals. But Worcestershire and Cheshire were the seat of the inland sea when it had contracted to the dimensions of a mere salt lake, and begun to throw down its dissolved saline materials. One of the Cheshire beds is sometimes a hundred feet thick of almost pure and crystalline rock-salt. The absence of fossils shows that animals must have had as bad a time of it there as in the Dead Sea of our modern Palestine.