16 CONCLUSIONS ON ANCIENT CLIMATES. 
Among these latter we must rank certain newly laid open 
fields of investigation, from which facts bearing on the point 
now under consideration have been gathered. I allude to the 
discovery of artificial objects in geological formations older than 
any hitherto recognized as exhibiting traces of the existence 
of man; to the ancient lacustrine habitations of Switzerland 
and of the terremare of Italy,* containing the implements of 
the occupants, remains of their food, and other relics of human 
life; to the curious revelations of the Kjékkenméddinger, or 
heaps of kitchen refuse, in Denmark and elsewhere, and of the 
peat mosses in the same and other northern countries; to the 
dwellings and other evidences of the industry of man in remote 
ages sometimes laid bare by the movement of sand dunes on the 
coasts of France and of the North Sea; and to the facts disclosed 
on the tide-washed flats of the latter shores by excavations in 
Halligs or inhabited mounds which were probably raised before 
the era of the Roman Empire.t These remains are memorials 
of races which have left no written records, which perished at a 
period beyond the reach of even historical tradition. The plants 
and animals that furnished the relics found in the deposits were 
certainly contemporaneous with man; for they are associated 
with his works, and have evidently served his uses. In some 
eases, the animals belonged to species well ascertained to be 
now altogether extinct ; in some others, both the animals and 
the vegetables, though extant elsewhere, have ceased to inhabit 
the regions where their remains are discovered. Irom the char- 
acter of the artificial objects, as compared with others belong- 
ing to known dates, or at least to known periods of civiliza- 
tion, ingenious inferences have been drawn as to their age; 
and from the vegetable remains which accompany them, as to 
the climates of Central and Northern Europe at the time of their 
production. 
* See two learned articles by Pigorini, in the Nuova Antologia for January 
and October, 1870. 
+ For a very picturesque description of the Halligs, see PLuny, V. H., Book 
phy (hale 
