Prof. NordensJiioM — Expedition to Greenland. 409 



VII. — Account of an Expedition to Greenland in the yeak 1870. 



By Prof. A. E. Nordenskiold. 



Foreign Correspondent Geol. Soc. Lond., etc., etc., etc.. 



Part III. 



{Continued from page 368.) 



BEFOEE proceeding to give an account of these changes in the fauna 

 of Greenland, I wish to draw attention to the possibility which 

 exists in these parts of obtaining a comparison between the units of geo- 

 logical and historical chronology, that is — if by collecting observations 

 and reports from many different localities, it be possible to determine 

 certain limits for the velocity with which the border of the inland ice 

 moves. One may arrive at the lower limit from the following con- 

 siderations. The breadth of the slip of border-land at Auleitsiviks- 

 fjord is about 60 miles, or 350,000 ft. The annual retreat can, of 

 course, never exceed the thickness ' of the covering that yearly 

 melts, divided by the sine of the inclination of the icy surface, which in 

 the places passed by us was nowhere less than 30°. It is hardly 

 probable that during a summer in Greenland an ice-layer of more 

 than 10 ft. can melt away, so that a yearly retreat exceeding 

 g—^ =: 20 ft., is not to be thought of. This would give for the time 

 that has been required for the uncovering of the outer strip of land 

 at Auleitsviksfjord a period of at least 17,000 to 18,000 years. But 

 this number is evidently too low, for neither the yearly falls of 

 snow nor the advance of the ice-mass has been taken into account, 

 as they of course ought to be ; and yet we have here to do with 

 a geological period, which undoubtedly forms but a small fraction 

 of tlie interval that has elapsed since the first appearance of man. 



The point at Sarpiursak forms a very level and extensive plain, 

 elevated about 60 to 150 feet above the sea, covered with a vegetation 

 of "lyng," moss and sedge, too scanty to conceal the clay which 

 forms the bottom of the plain. Similar formations in many other 

 places along the shores of Disko Bay and Auleitsiviksfjord have given • 

 rise to vast clay -beds, which attracted attention long ago in these parts 

 so ill supplied with clay. Our Greenlanders even mentioned that they 

 contained petrified shells and " Angmaksater " (a species of fish). 

 These fossils are also mentioned by Dr. Eink in his work on North 

 Greenland ; and he adds, that a collection which he had sent home 

 had been examined by Dr. 0. A. L. Morch, who found the shells 

 partly to belong to species still existing on the coasts of N. Greenland, 



1 Estimated at right angles to the 

 surface of the ice. The annexed cut 

 shows this more clearly. If G is the 

 surface of the ice in e.g. 1870, G' and 

 the same surface in 1871, then AG' /^^ 



is the thickness of the layer that has 

 melted; and the distance the ice has 

 receded is=AG': Sin V. The angle 

 V is, of course, determined by the 

 relation between the velocity of melt- 

 ing and the velocity with which the ice flows out of the higher parts of the glacier. 



