2 
Introduction 
and monasteries which have a historic 
or an artistic value, are spoken of as 
monuments of architecture and of 
art, — in German Bau- und Kunst- 
denkmaler." The expression is also 
applied to prehistoric remains, such as 
lake dwellings, stone circles, dolmens, 
and burying mounds which are spoken 
of as prehistoric monuments. 
All the above-mentioned objects are 
the result of man's activity ; but nature 
too has her monuments. Just as the 
ornamented stone obelisk is a monu- 
ment of art (Kunstdenkmal), and as 
the rude stone, erected by man in 
former ages to the memory of the 
dead, is a prehistoric monument, so 
too the erratic block, transported in 
past time by natural forces, constitutes 
a natural monument. Again, just as 
an artificially erected wall or mound of 
an earlier period may be a prehistoric 
monument, so the natural moraine or 
