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506 from the divers or owners of diving-apparatus. In this way the article may be got at first hand, without being weighted with

Alligators swallowing their Young.—Colonel Caleb G. Forshey, of the New Orleans Academy of Science, à propos of the question whether snakes swallow their young, states that this habit is certainly found among alligators. "That alligators swallow their young," says Prof. Forshey, "I have had ocular demonstration in a single case; and have the universal tradition of negroes and whites in this region of Louisiana, Mississippi, and Texas, that such is their habit. In the winter of 1843-'44, I was engaged making a survey on the banks of the Homochitto Lake. The day was warm and sunny, and, as I halted near the margin of a pond partly dried up, to pick up some shells, I started a litter of young alligators, that scampered off, yelping like puppies, and retreating some twenty yards to the bank of Lake Homochitto. I saw them reach their refuge in the mouth of a five-foot alligator. She evidently held open her mouth to receive them, as, in single file, they passed in beyond my observation. The dam then turned slowly round, and slid down beneath the water, passing into a large opening in the bank, beneath the root of an ash-tree. Doubtless this refuge is temporary, and the young are released at their own or the mother's pleasure."

Le Conte on the Origin of Western Mounds.—Prof. Joseph Le Conte, in the American Journal of Science, discusses the origin of the mounds with which the prairies near Puget Sound are studded, and from which they get the name of "mound prairies." These mounds are generally three or four feet high, and thirty to forty feet in diameter at the base. There are millions of them, and they stand so thickly as to touch each other at their bases, leaving no level space between. They consist wholly of a drift-soil of earth, gravel, and small pebbles, the intervals being thickly strewed with larger pebbles and small bowlders. The vegetation of the mounds is mostly ferns; the intervals are covered with fine grass only. Some have supposed that they are Indian burial-mounds; others have thought that they are artificial mounds, upon which were built huts of Indian villages. They have also been supposed to be large fish-nests, dating from the period when these prairies were the bottoms of shallow inlets of the sea. The author holds them to be the result of surface-erosion under peculiar conditions. In another part of the State, viz., between the Dalles and the upper bridge of the Des Chutes River, a distance of about thirty miles, the whole country is literally covered with mounds of this kind. Here they vary in size, from scarcely detectible elevations, to mounds five feet high and forty in diameter at the base; and in form from circular, through elliptic and long elliptic, to ordinary hill-side erosion-furrows and ridges. In regularity of size and position there is equal diversity; in some places being as complete as at Mound Prairie, while, in other places, they are of different sizes, and often separated by wide, pebble-covered spaces, as if they were but the remnants of a general erosion of the surface-soil. No one, says Prof. Le Conte, can ride over those thirty miles, and observe closely, without being convinced that these mounds are wholly the result of surface-erosion, acting under peculiar conditions. These conditions are, a treeless country, and a drift-soil, consisting of two layers—a finer and more movable one above, and a coarser and less movable one below. Surface-erosion cuts through the finer superficial layer, into the pebble-layer beneath, leaving, however, portions of the superficial layer as mounds. The size of the mounds depends on the thickness of the superficial layer; their shape depends much on the slope of the surface. The process once started, small shrubs and weeds take possession of the mounds, as the better soil, and hold them by their roots, and thus increase their size, by preventing or retarding erosion. The treelessness of Eastern Oregon has been produced gradually, since post-tertiary times, by the increasing dryness of the climate. We may imagine the mounds, therefore, as having been held by the struggling remnants of a departing vegetation. At Mound Prairie, however, the treelessness is probably produced by a contrary condition, viz., the extreme wetness of these lower level spots in winter.