THE DEPOSITS OF THE SEA-BOTTOM. ,y 



three specimens, one at the west coast of Greenland, and two southeast of Iceland, and only 

 one single grain in each specimen. 



Zeolites have been found sometimes as stuffing of small cavities in the basalt, but on account of 

 the smallness it has not been possible to determine the species, which would, however, also 

 be of small importance, as the different zeolites are found everywhere in Iceland and the Faroe 

 Islands; in a single specimen, no. II, between Iceland and Greenland a larger cavity was 

 found stuffed with a fine-grained rock, probably some zeolite ; it is likely to have come from 

 the ridge itself. 



Chalcedony has also been found as stuffing of small cavities; a single one of these was found 

 isolated in specimen 127 north of Iceland. 



Volcanic tufa is a rather common ingredient in the specimens; commonly it is only very little 

 characteristic, and resembles very much gray clay; but in the larger pieces are often seen 

 small grains of black volcanic rocks that are found in it. It has, with more or less certainty, been 

 pointed out in 36 specimens situated on all sides of Iceland, mostly to the southwest; of two 

 of these specimens it formed the chief ingredient, viz. in no. 2, between the Faroe Islands and 

 Iceland, and in no. 89, west of Iceland. 



Of the not volcanic ingredients has especially to be mentioned: 



Quartz, the most widely distributed of all the minerals in the specimens, forms the chief constituent 

 of most of the not volcanic specimens, and the only not volcanic ingredient in a great 

 number of volcanic specimens. Most frequently it is clear and colourless, also often brownish, 

 yellowish, or reddish, often more or less opaque; crystalline surfaces have not yet been found. 

 The quartz has altogether been met with in 69 out of the 79 specimens; the only specimens 

 absolutely free of quartz, were: no. 7, at the southeast coast of Iceland, nos. 8 — 12, west of 

 Iceland, and nos. no — 113, between Iceland and Jan Mayen; it forms the chief constituent 

 of 23 specimens, partly of all the specimens close to Greenland, partly of a great many speci- 

 mens surrounding Iceland on all sides, but generally at a rather large distance, and partly 

 of the specimens from a region north of the Faroe Islands. In many of these localities the 

 large mass of quartz might seem strange; if we regard, for instance, a large series of speci- 

 mens, nos. 45 — 48, and nos. 65 — 67, situated about 200 kins, south of Iceland, it seems rather 

 remarkable that already here the Icelandic ingredients should be so strongly eclipsed by the 

 quartz, the nearest native laud of which, Greenland, is at a distance of up to 1200 kms. from 

 these specimens. But the fact is still more remarkable when we take into consideration that 

 this series of specimens is situated across the territory of the Gulf-stream, and thus it would 

 be most likely to expect the circumstances to be as infavourable as possible for a transport 

 from the north or the northeast. As it is impossible to suppose that the Gulf-stream should 

 have carried material across the Atlantic, there would seem to be chiefly two possibilities 

 left: either that the quartz has its origin from ice-bergs that have strayed from the north 

 into this region, and have been melted by the influence of the Gulf-stream, or else that the 

 ice-bergs about at the south point of Greenland have come into the territory of the Gulf- 



