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Perhaps, also, we may regard it as, to say the least, highly 
probable, that in Northern Europe there have been three 
great epochs in the history of man — primary, secondary, and 
tertiary — the first of stone, the second of bronze, and the 
third of iron. This conclusion, which we owe in the first 
instance to the Northern and especially to the Danish Archae- 
ologists, has been much strengthened by the recent researches 
in the lakes of Switzerland. 
It is however probable, that the stone period will require 
much sub- division, and must be divided into at least two 
periods ; that of the drift on the one hand, and on the other 
hand, that to which the Danish Kjokkenmoddings and the 
Swiss Lake Habitations appear to belong. 
These Lake-dwellings or " Pfahlbauten," — a term whose 
nearest English equivalent is " Pile- works" — were made 
known to us in the following manner. 
In consequence of the extraordinary dryness and coldness 
of the weather during the winter months of 1853 and 1854, 
the rivers of Switzerland did not receive their usual supplies, 
and the water in the lakes fell much below its ordinary level, 
so that in some places a broad strand was left uncovered 
along the margin, while in others shallow banks were con- 
verted into islands. The water level of this season was, 
indeed, the lowest upon record. The lowest level marked on 
the so-called stone of Stafa was that of 1674, but in 1854 
the water sank a foot lower. These unusual conditions, though 
very unfavourable to navigation, enabled the Swiss Archae- 
ologists to make the important discoveries which we are about 
to bring before our readers. 
M. Aeppli of Meilen, on the Lake of Zurich, appears to 
have been the first to observe, in the bed of the lake, certain 
indications of human activity, which he justly supposed 
might throw some light on the history and condition of the 
earliest inhabitants of the Swiss valleys. In a small bay 
