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Page:Popular Science Monthly Volume 56.djvu/147

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FRAGMENTS OF SCIENCE.

Weed began his watch before full daylight in the morning, ten minutes before the bird got off from its nest, and continued it till after dark. During the busy day Mr. Weed says, in his summary, the parent birds made almost two hundred visits to the nest, bringing food nearly every time, though some of the trips seem to have been made to furnish grit for the grinding of the food. There was no long interval when they were not at work, the longest period between visits being twenty-seven minutes. Soft-bodied caterpillars were the most abundant elements of the food, but crickets and crane flies were also seen, and doubtless a great variety of insects were taken, but precise determination of the quality of most of the food brought was of course impossible. The observations were undertaken especially to learn the regularity of the feeding habits of the adult birds. The chipping sparrow is one of the most abundant and familiar of our birds. It seeks its nesting site in the vicinity of houses, and spends most of its time searching for insects in grass lands or cultivated fields and gardens. In New England two broods are usually reared each season. That the young keep the parents busy catching insects and related creatures for their food is shown by the minute record which the author publishes in his paper. The bird deserves all the protection and encouragement that can be given it.

 

Park-making among the Sand Dunes.—For the creation of Golden Gate Park the park-makers of San Francisco had a series of sand hills, "hills on hills, all of sand-dune formation." The city obtained a strip of land lying between the bay and the ocean, yet close enough to the center of population to be cheaply and easily reached from all parts of the town. Work was begun in 1869, and has been prosecuted steadily since, with increasing appropriations, and the results are a credit to the city. Golden Gate Park, Mr. Frank H. Lamb says in his account of it in The Forester, having a charm that distinguishes it from other city parks. It has a present area of 1,040 acres, of which 300 acres have been sufficiently reclaimed to be planted with coniferous trees. "It is this portion of the park which the visitor sees as one of the sights of the Golden Gate." As he rides through the park out toward the Cliff House and Sutro Heights by the Sea, "he sees still great stretches of sand, some loose, some still held in place by the long stems and rhizomes of the sand grass (Arundo arenaria). This is the preparatory stage in park-making. The method in brief is as follows: The shifting sand is seeded with Arundo arenaria, and this is allowed to grow two years, when the ground is sufficiently held in place to begin the second stage of reclamation, which consists in planting arboreal species, generally the Monterey pine (Pinus insignis) and the Monterey cypress (Cupressus macrocarpus); with these are also planted the smaller Leptospermum lævigatum and Acacia latifolia. These species in two or more years complete the reclamation, and then attention is directed to making up all losses of plants and encouraging growth as much as possible." The entire cost of reclamation by these methods is represented not to average more than fifty dollars per acre.

 

A Fossiliferous Formation below the Cambrian.—Mr. George F. Matthew said, in a communication to the New York Academy of Sciences, that he had been aware for several years of the existence of fauna in the rocks below those containing Paradorides and Protolenus in New Brunswick, eastern Canada, but that the remains of the higher types of organisms found in those rocks were so poorly preserved and fragmentary that they gave a very imperfect knowledge of their nature. Only the casts of Hyolithidæ, the mold of an obelus, a ribbed shell, and parts of what appeared to be the arms and bodies of crinoids were known, to assure us that there had been living forms in the seas of that early time other than Protozoa and burrowing worms. These objects were found in the upper division of a series of rocks immediately subjacent to the Cambrian strata containing Protolenus, etc. As a decided physical break was discovered between the strata containing them and those having Protolenus, the underlying series was thought worthy of a distinctive name, and was called Etchemenian, after a tribe of aborigines that once inhabited the region. In most countries the basement of the Paleozoic sediments seems almost de-