Page:Popular Science Monthly Volume 4.djvu/784

764 found in clay-beds; only their leaves fill them just as the radicles of water-plants fill the clay of the Tertiary lignite. It is, however, a fact that some of the lignite clay-beds, and those of the coal-measures, too, are clean or without admixture of vegetable remains, even of rootlets. But when the peat is beginning its growth at the surface of a somewhat deep basin of water, whose bottom has been rendered impermeable by the deposit of clay (which always precedes the deposit of woody materials), this surface-peat is often thick and compact before it is forced down and comes in contact with the clay; and, in that case, therefore, the clay is pure, or is not penetrated by roots or rootlets. There are, of course, some beds of impure lignite, whose origin is due to drifted wood, especially along large rivers. One is known at the mouth of the Rhone, in France. I have seen some deposits of the kind in Southeastern Arkansas, near the Wachita River. The great Red-River obstructions may become in time lignite-deposits. But all formations of this kind show their origin by their composition, viz., sand mixed with carbonized matter, sandy bottom, perforated, too, in various directions by drifted stems, etc. Nothing of this kind has been observed in the beds of lignite of the West, at least not in those which have come under my examination."

Geology of the Land of Moab.—Late explorations in the land of Moab by Dr. Tristam have disclosed some interesting geological features in that region. The doctor's observations were mainly confined to the highlands, which are in reality a set of terraces, or table-lands, rising to the eastward from the shores of the Dead Sea—attaining, in a distance of 35 miles, a height of between 4,000 and 5,000 feet. These table-lands are cut at right angles into deep gorges or ravines, by streams which now flow, or at some former time have flowed, westward into the Dead Sea. Some of the gorges are 1,800 feet deep, with perpendicular walls, from which a good idea of the geological structure of the region may be obtained. The surface of these highlands is composed of chalk, which rests upon a limestone formation, regarded by some as nummulitic and by others as Jurassic. The chalk and limestone together are from 1,200 to 1,500 feet thick. The limestone is supported by new red sandstone, the line where they join being well defined. It is from this line of junction that the hot springs, so celebrated in Roman times, gush forth. The water of these springs has a temperature varying from 100° to 143° Fahr. The salt-hills at the south of the Dead Sea, like the tablelands just spoken of, have been gouged out by the action of water, and present along their face numerous columns and pinnacles of salt, that are being rapidly worn down by the action of the weather.

Etiology of Typhoid Fever.—Prof. I. Buckman writes to the Gardener's Chronicle concerning the discovery of a microscopic fungus in water, the drinking of which was suspected of developing cases of typhoid fever. We give the main points of this communication. Some years ago Prof. Buckman examined the spout of a pump which had supplied water to a family attacked by typhoid. It was found to be lined with gelatinous matter. Under the microscope this substance was seen to contain some elegant branched confervoid or fungoid growths, intermixed with which were minute ovoid cells. As these fungoids require nitrogen for their nourishment, the author inferred that the supply came from some neighboring cesspool. He next went to the exit-drain of the town sewerage, and there found bits of sticks, leaves of water-plants, and the like, more or less covered with this same gelatinous matter.

The author next detected this fungus in water used by his own family, some of whose members were severely attacked with typhoid fever. A defective drain in the neighborhood of the dwelling having been set to rights, and the whole of the water pumped out, the water has since been of excellent purity. Having cited two other analogous cases, Prof. Buckman speculates as follows on the mode in which this fungus acts after having been admitted into the animal economy: "How it acts it would be difficult to determine, but it is at least conceivable that the spores of the fungus may get into the circulation, and bring about changes in the fluids, after the manner of