A STUDY IN CONTRASTS 93 
pressive example of intrusions of igneous rock is 
afforded by vertical walls of basalt which stretch 
across the valley. These magnificent dykes do not 
form continuous curtain walls from one side of the 
valley to the other, but the rocks are twice or 
thrice stepped on each side; the light brown wall 
of basalt towers against the sky at least too ft. 
above the upper level of the slope of the ravine. 
Its jagged and weathered ledge projects horizon- 
tally for some distance towards the middle of the 
valley and is then cut vertically down into a deep 
step, and this is repeated two or three times. At 
the foot of the valley the dyke crosses the stream as 
a resistant barrier where the water falls in a cascade. 
The ravine at Atanikerdluk (Fig. 46) stirred the 
imagination more than most of the many impres- 
sive scenes in other parts of Greenland. To anyone 
interested in geology a sense of sharp contrasts 
between the present and the past is so constantly 
evoked by the interpretation of the rocks that the 
wonder of it becomes less intense; but there are 
places and circumstances in which this sense of 
change from one age to another is awakened with 
especial force and vividness. The icebergs floating 
on the arm of the sea, a thousand feet below the 
ravine, are fragments of the shield of ice that has 
lain for thousands of years over nearly the whole 
of the interior of the country; the clumps of Arctic 
plants on the sloping banks of weathered sand- 
stone on either side of the glacial stream are in 
harmony with the climatic conditions of the present 
moment of geological history. The waifs and strays 
