66 POLAR PROBLEMS 



crossing what are now deep seas. Probably also there were lands 

 joining the New World with the Old in the early Paleozoic. 



Some of the Scandinavian geologists have published interesting 

 papers on this subject, but it would lead too far into paleontology 

 to go into details as to their results. 



Carboniferous 



The Carboniferous rocks which occur on the Parry Islands, Banks 

 Island, and at other points in the Arctic Archipelago present interest- 

 ing problems as to the distribution and economic importance of the 

 coal seams and also as to climatic conditions at the time of their 

 formation. There are many references to the finding of Carboniferous 

 coal of good quality in the reports of the early explorers, particularly 

 in the Parry Islands; but J. G. McMillan, the latest geologist to 

 visit the region, found little evidence of coal in quantity at some 

 points where earlier reports indicated valuable seams. General condi- 

 tions are very different from those of the United States and Europe, 

 since only the lower sandstones contain coal beds, while the upper 

 part of the Carboniferous consists of marine limestones. 



The indications as to ancient climates are puzzling. On the main- 

 land a tillite found along the Yukon-Alaska border is considered to 

 be of Permo-Carboniferous age and is compared with the tillites of 

 the same age in India and the southern hemisphere ;^ but the few plants 

 reported from the coal-bearing sandstones of the northwestern islands 

 are like those of North American and European coal measures, which 

 are always thought of as belonging to a warm climate. Good collec- 

 tions of the plant remains associated with these Arctic coals should 

 be made to see if they include representatives of the cool-climate 

 Gangamopteris flora found with the coals of India, Australia, and 

 South Africa. It is surprising to find warm-climate coal plants ten 

 degrees north of the Arctic Circle while a great ice age was under 

 way in the subtropics of India and the southern continents. 



Trl\ssic 



Triassic beds are the most widespread of the Mesozoic rocks, 

 forming a broad syncline to the north of the Parry Islands and in- 

 cluding Axel Heiberg, the other Sverdrup Islands, and much of the 

 northern part of EUesmere Island. If the Cape Rawson beds, once 

 considered Cambrian, are Triassic, as is now thought probable, the 

 syncline crosses the north end of EUesmere Island and touches north- 

 ern Greenland. 



8 D. D. Cairnes: The Yukon-Alaska International Boundary Between Porcupine and Yukon 

 Rivers, Geol. Survey of Canada Memoir 67, Ottawa, 1914, p. 93. 



