Proceedings of the Boston Society of Natural History, Band 22Boston Society of Natural History., 1884 |
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Häufige Begriffe und Wortgruppen
abdomen adults Ammonoidea Andesite annular lobes Anticosti appear argillite Bactrites basalt birds breeding Carboniferous Colias collection color conglomerate continents crust deposits Devonian Discitoceras dorsal lobes dorsal saddles dorsum earth's Edwardsii epiderm evidence F. W. Putnam feathers feet female forms Fox Bay funnels genus Geol geological glacial erosion glaciers Goniatites gravel gyroceran Hist horn cells hornblende ibid includes involute Island lakes larvae lateral lobes male miles mucous layer Naut nautilian Nautiloidea Nautiloids nearly nobis North observed oceanic olivine pair of saddles Paleozoic papillae Philodice present probably Professor Dana Propylite quartz reef rhyolites ridges rocks schists Scudder scuta sediments seen septa shells shore side Silurian similar species specimens stages structure surface sutures theory thickness tion Triassic valleys venter ventral lobes ventral saddles W. H. Edwards whorls yellow young Zirkel
Beliebte Passagen
Seite 174 - Practically, when a naturalist can unite two forms together by others having intermediate characters, he treats the one as a variety of the other, ranking the most common, but sometimes the one first described, as the species, and the other as the variety.
Seite 436 - Rau,79 who first described them, that " if the shape of the described implements (shovels and hoes) did not indicate their original use, the peculiar traces of wear which they exhibit would furnish almost conclusive evidence of the manner in which they have been employed ; for that part with which the digging was done appears, notwithstanding the hardness of the material, perfectly smooth, as if glazed, and slightly striated in the direction in which the implement penetrated the ground.
Seite 406 - At each discharge the frightened Murres fly from the rock in clouds, nearly every sitting bird taking its egg into the air between its thighs, and dropping it after flying a few yards. This was repeatedly observed during our visit, and more than once a perfect shower of eggs fell into the water around our boat.
Seite 7 - ... finished, expressed their gratefulness for the new powers the course had developed in themselves, and the fascinating pleasure they had experienced in learning to use their own eyes and hands in the study of things hitherto unapproachable for their uncultivated senses except through the deceptive mediation of books. When it is remembered that these teachers influence and mould the minds of thousands of young persons it is at the same time proved that what this laboratory has done and can do is...
Seite 7 - The great need of an institution for teaching field work cannot be properly estimated by the number of those who are attracted by the opening of such opportunities for study. The mental condition of those who attend, and what it has done for them, and the sphere of influence which it reaches through them, are the only true standards by which its present and future usefulness can be properly measured. Nearly all the pupils were persons who could be termed 'well educated...
Seite 468 - They are less abundant in the Radiolarian ooze, are rare in the Globigerina, Diatom, and Pteropod oozes, and they have been dredged only in a few instances in the terrigenous deposits close to the shore. These substances are present in all the deposits, but owing to the abundance of other matters in the more rapidly forming deposits their presence is masked, and the chance of dredging them is reduced. We may then regard the greater or less abundance of these materials, which are so characteristic...
Seite 125 - Toar and Molasses in the vicinity of Baracoa, the reef in question was completely interrupted, and these streams discharge into broad, open bays ; while the lower portions of their valleys show, equally with the harbors, that the land is sinking. They are half-drowned valleys, filled to a considerable depth with land detritus, conditions which could not exist if the land were rising or had recently risen. But the most satisfactory evidence that the ancient reefs of Cuba were not formed during periods...
Seite 257 - Silurian, but only one short series, the Nautilinidae, arises from the common trunk of straight cones. The close-coiled shells of this one family became the stock form for the whole of the Ammonoidea. The Nautiloidea of the Mesozoic are all nautilian forms, and their genetic series do not present the rapid changes of form observed in the Paleozoic ; they are all close coiled and have, as observed by M. Barrande, small umbilical perforations. This same statement applies also to the Ammonoidea ; when...
Seite 468 - In order to account for the accumulation of all these substances in such relatively great abundance in the areas where they were dredged, it is necessary to suppose the oceanic basins to have remained the same for a vast period of time. The sharks' teeth, ear-bones, manganese nodules, altered volcanic fragments, zeolites, and cosmic dust, are met with in greatest abundance in the red clays of the central Pacific, at that point on the earth's surface farthest removed from continental land. They are...
Seite 39 - Ice, or glaciers, by their immense expanding powers, must beyond doubt have produced this change in their original form, from this circumstance, that they were continually sliding downwards from the higher mountains to the lower districts and, by this progressive motion, carried with them the masses of stone which they had torn from the mountains.