GEOLOGY AND SCENERY OF NORTHEAST COAST 115 
across New Jersey, Pennsylvania, Ohio, Indiana, and so on 
to the plains of the Upper Mississippi Valley and Northwest 
Territories of Canada. The total area of this ‘‘ Labrador’”’ 
or ‘“‘Laurentian’’ ice-cap was over two millions of square 
miles. In the central part its thickness grew to be at 
least six thousand feet. There is evidence to show that even 
Mt. Washington (6288 feet in altitude), together with all 
other peaks of New England, was covered by the flooding 
ice. 
Investigation much less thorough than has been given to 
the Labrador glacier has suggested that similar, independent 
ice-caps were formed on the heights of Newfoundland and 
on the plateau northwest of Hudson Bay (the “ Keewatin”’ 
Glacier), each having centrifugal flow. 
The causes for the disappearance of the ice-sheets are 
as stimulating to debate among glacialists as the conditions 
that led to the growth of the glaciers. Fortunately for 
a scenographic account of the Labrador, these intricate 
theoretical questions need not detain us; suffice it only to 
note the fact that, after a period of prolonged activity, the 
ice gradually melted away. Not an acre of the old ice has 
been found on the mainland of North America. It is 
possible that the Grinnell Glacier, the relatively diminutive 
ice-cap of southern Baffin Land (Meta Incognita), repre- 
sents a still lingering portion of the mightier glacial flood, 
but so little is known of the Grinnell that a former connec- 
tion of the existing and the vanished ice-sheet cannot be © 
asserted. On the contrary, it may be that the reported | 
twelve hundred square miles of ice on the Meta Incognita 
belong to another independent centre of ice-accumulation. 
The solution to this problem and the interest which always 
