De Geer.] 
45(5 
I'M nv iS, 
sediments of Pleistocene age have been leveled in Europe and 
in America, it is nevertheless very hard to find any method for 
determining their limits with great accuracy. 
As far as I can see, that described below is the most suitable 
and perhaps the only possible method for this purpose. I have 
tested it in the northern part of Europe during the last ten years 
and by way of comparison in the eastern parts of North America 
during the autumn of 1891. In this paper I shall especially de- 
scribe and discuss the results of the last named investigations, but 
as these point to a very close analogy with the corresponding phe- 
nomena in northern Europe, it seems appropriate to give first a 
general view of the latter. 
Investigations in Europe. 
During the summer of 1882 I spent three months in Spitzbergen 
studying the glacial deposits and the raised beaches. Though 
these were very instructive for the study of the origin of shore- 
lines in general, the conditions were not favorable for an accu- 
rate determination of the uppermost marine limit, the land being 
rather mountainous, precipitous, and destitute of till. 
Since that time I have used every opportunity to discover and 
determine the marine limit in Sweden. The method I have used 
is the following : On every occasion I start with the most recent 
fossils in marine deposits ; with the aid of the topographic map I 
select a drift-covered hill of sufficient height with moderate slope 
and with a situation as open as possible to the ancient water-body 
and as near as possible to a point previously leveled. 
Above the water-laid clay and sand there is in most cases a belt 
of gravel, and still higher, where sediment is almost wanting, 
there are more or less conspicuous marks of erosion and water- 
wash up to a definite horizontal limit. In favorable localities this 
can be determined with an accuracy of from a few feet to less 
than one foot. Later on I will give a more detailed account of 
the methods I have employed for these determinations. I will 
only emphasize here that while geologists have too often measured 
the highest conspicuous shore-lines which happened to be devel- 
oped in a certain locality, I have used such figures only when 
nothing else was available. On the other hand I have always 
tried to choose hill-slopes so uniform that evidently the till above 
