REVIEWS 121 
on the depth and relative saltness of the sea. In studying the marine 
diluvium of Denmark, the author has found it insufficient to make the 
basis of classification consist of the structure of the beds and the char- 
acter of the previously known fauna only. He now proposes the fol- 
lowing classification based on the differences in the foraminifera con- 
tained in these beds. 
a. Deposits with a temperate fauna, comprising formations of inter- 
glacial age (probably in every locality studied). A part of these beds 
seem to belong to an age of comparatively warm climate, while another 
part appears to belong to a period of comparatively cold climate. 
6. Deposits with an arctic or boreal fauna. This division comprises: 
I. The older Yoldia-clay. 
II. The later Yoldia-clay. 
III. The Zirphzea-bed. 
The Cyprina clay belongs to the deposits that have a temperate 
fauna. Of its 13 foraminifera, eight forms are cosmopolitan in their 
habitat, two are found in southern waters, ranging as far North as to 
the Shetland Islands, while two are northern forms occurring as far 
South as Valencia. One form is not known in the present seas. ‘This 
indicates climatic conditions identical with the present. The nature 
of the molluscan fauna of this clay corroborates this evidence. A sum- 
mary is made of the literature on the structural relations of the Cyprina- 
clay. While the author admits that its exposures, so far as observed in 
Denmark, do not decidedly speak against the view that it is preglacial, 
he believes that there are good grounds for regarding it as being 
formed later than the oldest border clay on these islands. It has inno 
place been seen in an undisturbed condition under the bowlder clay 
and resting directly on preglacial deposits. The bowlder clay associ- 
ated with it often contains a large number of foraminifera, but it lacks 
those forms which are characteristic of the Cyprina-clay. Hence this 
bowlder clay can not very well be later than the Cyprina-clay, for, if 
this were older some of its fossils would have been likely to have become 
mixed into the superimposed morainic material. The high and varied 
tilting of the bed in most localities indicates, however, that it has been 
disturbed by glacial action at some time. In samples of a gray clay 
from Jutland, the author has found a fauna also indicating a temperate 
climate. 
In Holstein several localities have beds of gravel, sand, and clay 
with foraminifera and molluscs indicating biological conditions 
