332 gieseckI: on the geology of Greenland. 



the Island Ujorbik. In Ameraglikfiord, in 65° 4', there is a small 

 island, where the clay-slate forms small layers in fine-grained 

 granite ; fine cubes of iron-pyrites, with various truncations, 

 occur in this slate, which is greatly decomposed. Some small 

 islands in the south-east of Disko Bay consist of clay-slate, with a 

 variety of small beds and layers, viz., very ironshot hornblende, 

 with small garnets, whet-slate, granular hornblende, and green- 

 stone. This clay-slate may perhaps belong to the class denomi- 

 nated *' Transition rocks." 



5. Porphyry is very common in the south of Greenland, 

 from Cape Farewell to the 64th degree of latitude ; but it is 

 generally found towards the interior of the continent, forming 

 insulated rocks. In the interior of the Firth Igahkko, at 

 Akulliaraseksoak, hornstone-porphyry is found, very distinctly 

 stratified, and resting upon fine-grained granite, containing large 

 crystals of reddish-white, flesh-red, and tile-red felspar, and 

 another mineral of a talcose appearance, crystallised in six-sided 

 prisms, and hitherto unknown. The mass of the porphyry is 

 brownish-red, and passes in some places into claystone forming 

 clays tone-porphyry, the crystals then becoming less distinct. Horn- 

 stone-porphyry, with a few very small crystals of felspar, occurs 

 also in an adjacent firth called Tunugliarbik. This rock rests 

 upon Old Red Sandstone.* The porphyry is very much decom- 

 posed. It is of a brown-red colour, and is called by the natives 

 auhpadlrtoh, that is, blood-red rock. It contains small layers of a 

 brown-red iron-ochre, wliich the Greenlanders use as a dyeing 

 material, to embellish their utensils, and the interior of their 

 houses, a species of luxury they have learned from the Euro- 

 peans. 



6. Syenite, and all the porphyritic rocks belonging to the 

 Primitive and Transition Trap-lormation, are found in great abun- 

 dance in this country. Hornblende is a mineral which occurs 

 almost everywhere. A kind of coarse-granular syenite, composed 

 of coarse-granular Labrador-felspar and crystallised common 

 hornblende, rests upon fine-grained granite at the mountain 

 Illejutit, or Redekammen, 61° lat., in the neighbourhood of that 

 extensive bed of sodalite, sahlite, and hornblende, which has been 

 already mentioned. This Labrador-syenite occurs also at the 

 mountain Kognek, 62° lat., upon granite of a coarser grain. In the 

 vicinity of the mountain. Kognek is a group of more than 50 

 islands, lying in a western direction, in Davis' Strait, and called 

 by the natives Kittiksut, from kitta, west. These islands form 

 round-backed low hills, and consist of common felspar, of yellow- 

 ish-brown and leek-green coloin's, and common hornblende of 

 raven-black and sometimes velvet-black colour, accompanied by 

 small four-sided prismatic crystals of zirkon of red-brown and 

 purple-red colour, with fine-grained common magnetic ironstone 

 interspersed, and very little black mica. In some pai'ts of the 

 rock allanite occurs, of a pitch-black colour. The rocks are 

 somewhat ironshot, and disintegrated on their surface. 



* The relative age of this sandstone has not been determined. — Editor. 



