THE GEOLOGY OP THE ARCTIC COASTS. 563 



by Sir Charles Giesecke in 1821. These appear to separate the 

 lower plant-bearing beds (2000 to 3000 feet) from the upper or 

 lignitic series, which, however, contains the same flora which reap- 

 pears in the plants collected by the late Expedition from the 

 Miocene rocks of Lady-Franklin Eay, recently described before 

 the Society by Prof. Heer, in Jan Mayen Island, and in the black 

 shales of Cape Staratschin, in Spitzbergen, and in the brown coals 

 of Franz- Joseph Land. 



The Spitzbergen beds are remarkable for a marine bed being 

 intercalated in the estuarine series, generally characteristic of the 

 Arctic area. Amongst the fossils occur Terebratula grandis, Den- 

 talium incrassatum, Corbula Henkelinsi, and Natica phasianella. 



The marine beds appear to be exceptional, and the greater mass 

 of the 1500 feet of strata of Miocene age are of freshwater origin, 

 and contain brown coal, plant-remains, and twenty-six insects. 



Of the thirty species of plants obtained from the Grinnell-Land 

 Tertiary beds*, discovered by the Expedition, eighteen occur in the 

 Spitzbergen flora, with which, Prof. Heer points out, it closely 

 approximates, and marks somewhat colder conditions than are ex- 

 pressed by the character of the plants in the Disco-Island Miocenes, 

 11° further south. 



Six species of the Grinnell-Land flora are common to Europe, one 

 of them being the fir (Pinus abies), which in Miocene times was 

 confined to the Arctic zone, and now in Scandinavia never ranges 

 north of 69|° N. (See Table of Tertiary Deposits, p. 564.) 



Glacial and later deposits. — There is no point of Arctic geology of 

 greater interest than the occurrence of water-margins at successive 

 elevations in Smith Sound, rising to heights of from 200 to 300 feet, 

 in situations where wave-action was impossible. These ancient sea- 

 margins are most persistent in bays, inlets, and narrow arms of the 

 sea, and are still in process of formation. 



Subaerial denudations of the surfaces of the cliffs cause vast masses 

 of material to fall during the thaw of the short summer, on a scale 

 so gigantic that the mind fails to realize it, unless it has been actually 

 witnessed. 



The base of the cliff is concealed by a talus made up of a shifting 

 mass of material resembling those known as " screes " in the English 

 lake-district, and like them chiefly supplied by fragments from the 

 deep gullies or " rakes " which seam and scar the cliffs above, and 

 act as channels for the passage of the frost-worn material of the 



* Already described in the Quart,. Journ. Geol. Soc. vol. xxxiv. p. 66, by Prof. 

 Heer. The coal associated with these beds has recently been analyzed by Mr. 

 E. J. Moss, F.C.S., and found to contain : — 



Carbon 75*49 



Hydrogen 5 - 60 



Oxygen and nitrogen 9*89 



Sulphur 0-52 



Ash 649 



Water 2*01 



10000 



—Scientific Proc. Boyal Dublin Soc, 1877. 



