Sketch of the Geology of the Arctic Regions. 1 3 



8. Limestone. — All the varieties of this rock are composed of 

 granular concretions loosely aggregated, and the only colors observed 

 were snow v^^hite, and greenish white. The minerals which occur 

 in it are small crystals of mica, augite, augite with serpentine forming 

 verd-antique, precious serpentine, sphene, and titanitic iron, graphite 

 or black lead. 



9. Porphyry. — But one specimen was observed, which was eurite 

 porphyry, a variety of granite. 



TRANSITION ROCKS. 



1. Red and variegated sandstone, transition quartz rock, recent 

 greywacke slate, drawing slate, flinty slate, and limestone. There 

 are many varieties of red sandstone, and quartz rocks of which there 

 are white, grey, purple, and red, in others the colors arranged in 

 stripes. The white and grey hard varieties, may be considered, a 

 transition quartz rock, the red and variegated, as transition red sand- 

 stone, or recent greywacke. The minerals occurring in them are 

 felspar, mica, chlorite, pale rose quartz, epidote, rock crystal, schorl, 

 crystals of iron glance, and red iron ore, scaly foliated iron glance, 

 compact red iron ore, copper pyrites, quartz rock, quartz with mag- 

 netic iron ore. 



2. Greywacke, and greywacke slate, witli disseminated iron py- 

 rites, are found in two or three instances. Transition clay slate was 

 observed only in Bouverie Island. 



3. Flinty slate, and drawing slate, with disseminated iron pyrites 

 were seen, but were of rare occurrence. 



SECONDARY ROCKS. 



1. lAmesione, bituminous shale, and secondary trap, flint and con- 

 choidal hornstone imbedded in it. It contains various organic re- 

 mains, among which, are corals, trilobites, and a species of orthoceras, 

 with many fossil shells. 



2. Specimens af bituminous shale were met with, but no othei' 

 trace of the coal formation. 



3. Secondary greenstone, sometimes containing titanitic iron ore^ 

 sometimes iron shot and porphyritic, and at others crossed with veins 

 of calcareous spar. 



