has gone even further and determined three well-defined stages in the final retreat of the Würm glaciation. The stages correspond to temporary advances during the period of retreat. Such stages have left their traces so distinctly in the region about Innsbruck that local names have been applied to them—Bühl, from Kirchbühl, at an elevation of 500 meters; Gschnitz at 1.200 meters; and Daun at 1,600 meters, the latter, of course, being the most recent.
The barbaric races with which the Romans had to contend had a knowledge of iron. It is estimated that the bronze age had its beginning some 3,500 years ago. The Alps were then either in- habited or visited throughout their extent by man. We find, for example, bronze weapons in the Flüela pass of the upper Engadine. The Flüela pass was invaded by ice of the Daun stage. The latter, therefore, antedates the bronze age. Prehistoric copper mines have been discovered at two localities in the Austrian Alps. One of these lies at the southern foot of the Übergossene Alp, near Salzburg, at a height of 1,500 meters. Neolithic implements were found in the old shafts. Now this locality (Mitterberg) is near the timber line, and a slight depression of this would render it difficult to establish smelters there. The other copper mine is southeast of Kitzbühel in the Tyrol, at a height of 1,900 meters. This mine also must have been occupied later than the Daun stage, at which time the region lay very near the snow line and was uninhabitable.
Even the whole neolithic period in Switzerland is younger than the Daun stage, whose snow-line lay 300 meters lower than to-day. The minimum time, therefore, that separates us from the Daun stage must be at least 7,000 years.
A very long interval of time separates us from the closing epoch (Magdalenian) of the paleolithic period. For we find on the borders of Lakes Constance and Geneva animal remains of the Magdalenian epoch in terraces that are 20 to 30 meters above the present level of these lakes. Magdalenian industry is found in Switzerland well within the area covered by the Würm glaciation. But such stations have not yet been found within that covered by the Bühl stage. It may be taken for granted, therefore, that the Magdalenian industry is not older than, but may be contemporaneous with, the Bühl stage, which corresponds, by the way, to the Champlain stage in North America.
The rock-shelter of Schweizersbild was occupied by paleolithic man after the Würm glaciation had retreated across the Rhine from Canton Schaffhausen. Here 25.000 stone implements have been found by Nüesch; also many bone implements and some engravings, one being of the mammoth. The paleolithic layers were covered in turn by successive deposits belonging to the neolithic bronze and Roman periods. Taking the thickness of the deposit left since Roman times
