Page:Physical Geography of the Sea and its Meteorology.djvu/357

Rh Carolinas that Brooke's apparatus brought up from the bottom of the Atlantic off the Irish coast.

617. Their suggestions.—The unabraded appearance of these shells, and the almost total absence among them of any detritus

more complete account, which I hope soon to publish. The specimens examined by me were as follows, viz.: "No. 1. Sea bottom, 2700 fathoms; lat. 56° 46′ N., long. 168° 18′ E. ; brought up July 19, 1855, by Lieutenant Brooke, with Brooke's lead. "No. 2. Sea bottom, 1700 fathoms; lat. 60° 15′ N., long. 170° 53′ E.; brought up as above, July 26, 1855. "No. 3. Sea bottom, 900 fathoms; temperature (deep sea) 32°, Saxton; lat, 60° 30′ N., long. 175° E. "A careful study of the above specimens gave the following results: "1st. All the specimens contain some mineral matter, which diminishes in proportion to the depth, and which consists of minute angular particles of quartz, hornblende, feldspar, and mica. "2nd. In the deepest soundings (No. 1 and No. 2) there is the least mineral matter, the organic contents, which are the same in all, predominating, while the reverse is true of No. 3. "3rd. All these specimens are very rich in the silicious shells of the Diatomaceæ, which are in an admirable state of preservation, frequently with the valves united, and even retaining the remains of the soft parts. "4th. Among the Diatomes the most conspicuous forms are the large and beautiful discs of several species of coscinodiscus. There is also, besides many others, a large number of a new species of rhizosolenia, a new syndendrium, a curious species of cheetoceros, with furcate horns, and a beautiful species of asteromphalus, which I propose to call Asteromphalus Brookei, in honour of Lieutenant Brooke, to whose ingenious device for obtaining deep soundings, and to whose industry and zeal in using it, we are indebted for these and many other treasures of the deep. "5th. The specimens contain a considerable number of silicious spicules of sponges, and of the beautiful silicious shells of the polycistinese. Among the latter I have noticed Cornutella clathrata of Ehrenberg, a form occurring frequently in the Atlantic soundings. I have also noticed in all these soundings, and shall hereafter describe and figure, several species of eucyrtidium, halicalyptra, a perichlamidium, a stylodictya, and many others. "6th. I have not been able to detect even a fragment of any of the calcareous shells of the polythalamia. This is remarkable from the striking contrast it presents to the deep soundings of the Atlantic, which are chiefly made up of these calcareous forms. This diflference cannot be due to temperature, as it is well known that polythalamia are abundant in the Arctic Seas. "7th. These deposits of microscopic organisms, in their richness, extent, and the high latitudes at which they occur, resemble those of the antarctic regions, whose existence has been proved by Ehrenberg, and the occurrence in these northern soundings of species of asteromphalus and chsctoceros is another striking point of resemblance. These genera, however, are not exclusively