38 THE DEPOSITS OF THE SEA-BOTTOM. 



stream, and have been melted, whereupon the qnartz has been transported towards the 

 northeast This question cannot be decided, unless an examination is made of specimens 

 situated to the south of those mentioned here. As the distribution of the quartz coincides so 

 closely with that of the other not volcanic minerals and rocks, it will be better to treat 

 these matters together in a later section. 



Feldspar, as has been mentioned, may be of volcanic origin; in most instances, however, it is found 

 as red orthoclase together with the quartz, but always in small quantity. It has altogether 

 been found in 35 specimens, partly alone, partly as an ingredient of crystalline rocks together 

 with quartz and other minerals. The feldspar does not in any of these specimens form an 

 especially large percentage. As to the distribution nothing more can be given than the 

 fact of its being absent in most of the strongly volcanic specimens. Crystalline surfaces 

 have never been observed, always cleavage planes. 



Hornblende has often been found as an ingredient of crystalline rocks, single only one piece in 

 specimen no. 19, east of the south point of Greenland. 



Garnet in loose grains has only been found in three specimens: no. 90, between Greenland and 

 Iceland, no. 116, south of Jan Mayen, and no. 143, north of the Faroe Islands, at all three 

 places as red garnet, probably almandine ; the origin of the garnet is probably to be sought 

 in Greenland, and the fact that this mineral has not been found in the specimens nearest to 

 Greenland, may be regarded as a mere casualty; among the finer ingredients it is found in 

 especially large amounts in some Greenland specimens. 



Biotite has been found in 12 specimens without any especially characteristic distribution, as well of 

 volcanic as of not volcanic habitus. It is only found in single leaves, and plays only a 

 minor part, as is also the case with the 



Muscovite that has been observed in 6 specimens, most of them south or southwest of Iceland, a 

 single one north of the Faroe Island. 



Granite and Gneiss, as the other crystalline rocks, are only with difficulty to be distinguished in 

 so small pieces as those mostly found. To this category I have referred any grained com- 

 pound of quartz and feldspar commonly together with some dark mineral, either hornblende 

 or biotite, or sometimes muscovite and garnet. Such rocks have been observed in 14 speci- 

 mens, of which three from the west coast of Greenland, one south of Cape Farewell, three 

 southwest of Iceland; of these latter has to be noted a very large piece of gray granite or 

 gneiss (of a diameter of 3°™) in no. 83, while in the other specimens only a few small 

 fragments were found. Further were found a few pieces of granite or gneiss in two speci- 

 mens south and southeast of Greenland, in three specimens between Iceland and the Faroe- 

 Islands, and in two specimens between the Faroe Islands and Greenland, in one of which 

 latter, no. 92, numerous pieces were found of a very fine-grained dark gray variety, more 

 prominent than the other ingredients of the specimen. From this rock an even transition 

 is found to 



Fine-grained or compact rocks of quartz, which cannot be more exactly determined on account 

 of the small pieces in which they occur; they may be partly quartz-porphyry or kindred 



