COASTS VISITED BY THE AECTIC EXPEDITION. 599 



Pelecypod Mollusca lived within the Arctic circle during the long 

 ages of Palaeozoic time. Five genera and 150 species of Silurian 

 Monomyaria are known in the North-American area, and 27 genera 

 and about 230 species of Dimyarian forms, yet none have been 

 collected north of lat. 60°. Only three species have been found in 

 Newfoundland — two in the Calciferous group and one in the Chazy 

 series, and in the Levis formation only two. Adding this to the few 

 Gasteropoda found, it almost appears that littoral conditions scarcely 

 existed through these eras over a very large area north of lat. 70°, a 

 circumstance somewhat confirmed by the rich Coral fauna, Polyzoa, 

 Heteropoda, Brachiopoda, and Cephalopoda (deep or open sea 

 or pelagic forms) occurring so persistently in all the collections 

 made. We could scarcely have failed to recognize the presence 

 even of portions of the shells of this division of the subkingdom 

 Mollusca proper had they occurred. As above stated, none have 

 been found either in the Silurian or Carboniferous series in high 

 latitudes. This cannot in any way be due to temperature, as the 

 fossil fauna now represented as far north as 82° 43' could not have 

 existed at low temperatures. Probably along the coast it was fiord-like, 

 with the water deep; and littoral conditions may not have existed to 

 any extent, there being no true beaches. The Coral fauna living in 

 the deeper portions of the sea were associated with the Brachiopoda 

 and Polyzoa. The Cephalopoda and Heteropoda being pelagic would 

 readily account for their presence with the other classes mentioned. 

 In no other way can we account for the absence of the Lamelli- 

 branchs. We have now existing in the highest latitude an abundant 

 and characteristic Lamellibranchiate fauna, which occurs also in Post- 

 Tertiary beds as high as latitude 82° 30', at Shift-Rudder Bay, 

 where in the " grey mud deposits," up to an altitude of 200 feet, 

 Astarte borealis, Mya truncata, Saxciava rugosa, Carclium islandicum, 

 Leda arctica, L. pernula, and Pecten groenlandicus abounded. At 

 Lincoln Bay, Grinnell Land, lat. 82° 8', the same species occur 

 50 feet above sea-level, the shells covering an area of many miles. 

 At Dumb-bell Harbour, lat. 82° 30', and 400 feet above sea-level, 

 Feilden found the same Mollusca and calcareous "rods of Funi- 

 cularia quadrangularis " abundantly distributed. This species, ac- 

 cording to Mr. Norman, occurs at Oban, and was dredged by the 

 1 Porcupine ' in the Minch (1869) ; it is also found in the Kattegat, in 

 the Scandinavian seas. Again, on the plateaux at Ploeberg Beach 

 lat. 82° 27', and at an elevation of 800 feet, the valves of Mya 

 truncata occur ; even up to an elevation of 1000 feet, at Watercourse 

 Bay, lat. 81° 44', these mud beds with scratched erratics and Mya 

 truncata, Saxciava rugosa, Astarte borealis, and Pecten groenlandicus 

 were met with. Thus through the presence of these Mollusca 

 we obtain clear evidence of the continuous elevation of the 

 Polar land (1000 feet) since the close of the Miocene epoch, or that 

 age when our modern Arctic and boreal fauna became established. 

 The causes influencing the paucity of species, as compared with 

 individual abundance, can only be accounted for by a knowledge of 

 the physical conditions under which life was and is sustained within 



