GTESECKf: ON THE GEOLOGY OF GREENLAND, 335 



of them present pyramidal, some conical forms, and some are 

 entirely flat. Their stratification is very nearly horizontal ; and 

 the valleys between the mountains are generally narrow. There 

 is no doubt that some of the mountains have been separated by 

 very recent eruptions of rapid torrents. 



On some parts of Disko Island beds of brown-coal occur in 

 Floetz-trap ; they rest upon yellowish-white coarse-grained sand- 

 stone, which is very friable. Large balls of iron-pyrites are 

 imbedded in it. The beds of coal are generally divided from each 

 other by strata of fine-grained sandstone, and are of very unequal 

 thickness. In some places of the east coast of Disko Island, in 

 the Waygat, the sandstone becomes harder, and carbonised im- 

 pressions of leaves are found in it, which are similar to those of 

 Soi'bus and Angelica. 



The coal of Disko Island is common brown-coal, of a slaty 

 texture ; it burns very easily, but it leaves a great residuum in 

 the form of white ashes, which have a slaty texture, and some- 

 what resemble the polishing slate from Bilin in Bohemia. A very 

 remarkable variety of brown-coal, passing into bituminous wood, 

 occurs in a small bed at Hare Island. It is of slaty texture ; and 

 honey-yellow amber, in numerous grains of various size_s, is 

 disseminated parallel to the cleavage of the coal. It rests upon 

 ash-grey coarse-grained sandstone, is covered with grey common 

 clay, and belongs undoubtedly to the newest brown-coal forma- 

 tion. At Koome in Omenaksfiord, native capillary and fibrous 

 sulphate of iron, of a beautiful green colour, is found in the clifi*s 

 of the brown-coal. All the Greenland coal is subordinate to 

 Floetz-trap. 



Alluvial land has been formed at the end of every bay and 

 firth of the coast ; and, in addition to grey and greyish -white 

 sandy clay, it contains fragments of the neighbouring mountains. 

 This formation is daily increasing, and contains no metallic 

 substance, except magnetic iron -sand, with which it generally 

 abounds. 



XLIII. —On the Mineralogy of Disko Island. By Sir 

 Charles Giesecke, F.R.S. Edin. 



[From the Transact. Roy. Soc. Edinburgh, vol. ix., 1821, 

 p. 263, &c. Read April 4, 1814.] 



[The Weruerian terms " Primitive rocks," *' Floetz Trap," and '' Floetz 

 " formation " are used as in the preceding paper.] 



Disko Island is situated in front of a bay in the continent of 

 Greenland, within Davis' Strait, known by the name of Disko 

 Bay, which is sometimes called, particularly in the old Dutch 

 charts, Sydost (South-east) Bay. This name is derived from an 

 ininionsc eiirvatiire, screened by innumerable islands, made in the 



