CHANGES IN LEVEL OF THE LAND 301 
are two quite different changes,—one of broad uplift 
or depression, which affects great areas, but works 
slowly, and which, because of its widespread effect, 
may be called continental; the other, a more local 
and more rapid movement associated with mountain 
action. The latter is certainly a movement of the 
land, for this has actually been seen to occur during 
earthquakes (p. 358). Moreover, as a result of this 
land movement, rocks are broken and folded, thus 
showing actual changes in the level of the crust. 
Of the broader continental movements, there is also 
distinct evidence that m some cases at least, it is a posi- 
tive change in the level of the land. This is true, for 
instance, of Sweden; for there is a rising in one part 
and a sinking in others, while on some of the neighbor- 
ing coasts there is little if any change. In this region 
the water level would certainly not alter perceptibly, and 
yet with such different results at places near together. 
The movements in the interior, mentioned below, are 
also evidences of actual change in the land level. 
It is probable that as a result of various causes 
there are slight variations in the sea-level; but these 
would affect large areas, and possibly, in the course of 
great periods of time, even produce notable results; yet 
certainly these are not of so much importance as the 
movements of the land itself. The sea is a mobile body, 
and any change would be widespread. It is also an 
