Prof. K. A. von Zittel—On the Mammata. 455 
the middle of the house. The result of this change was to show, I 
believe, that the periodic movements indicated by the H.W. level 
may in part arise from bendings in the walls of the house, caused 
by the expansion and contraction of the roof. 
Referring to the above table, it will be seen that the inclination 
towards the east changed rather irregularly, in three years being 
considerable and in the other two slightly retrograde. During the 
second year of the observations there was an extraordinary move- 
ment of 14 minutes between Nov. 13, 1879, and Jan. 28, 1880, in 
a direction a little south of east. The masonry on which the levels 
rested is not, however, totally disconnected from the structure of 
the house; and it seems to me most probable that the non-periodic 
movements indicated by the E.W. level are due to a settling of the 
house in the line of greatest slope of the ground outside. 
On the other hand, the change of inclination towards the north 
has taken place much more regularly, the annual change varying 
from 0"-90 to 2-00, and being 1/52 on an average for the five years." 
So far as J am aware, there is nothing of a purely local character 
to account for this movement. It seems to be independent, or nearly 
so, of that which takes place in an easterly direction; for it may 
exist without the latter. ‘There can hardly be any creeping of the 
soileap or settling of an old house along a line nearly at right angles 
to that in which the land dips and in reality inclining upwards. It 
is possible that the levels may beat fault, for, as before remarked, 
they are by no means perfect instruments ; but the regularity of the 
movements is in favour of the view that they are caused by a real 
tilting of the ground itself, a tilting which must result in the very 
slow but still measurable growth of the Lake of Geneva. 
VI.—Tue Gerotocicat Devetopment, Descent AND DISTRIBUTION 
oF THE MaMmMALta. 
By Prof. Karn A. von Zrrrer, Ph.D., For. Memb. Geol. Soc. Lond. 
Professor of Paleontology in the University of Munich. 
(Continued from page 412, Vol. X. September, 1893.) 
is addition to the localities in Europe and N. America, another area 
for Tertiary Mammals has in very recent times been laid open 
to view in the Southern part of Argentina, which promises in the 
wealth of its contents to exceed those previously known. A few 
scattered remains from the Tertiary beds of the neighbourhood of 
Santa Cruz in Patagonia were already known more than forty years 
ago, but it is only lately, through the work of Burmeister and 
Moreno, and more particularly through the indefatigable researches 
of Florentino Ameghino, that a more complete insight into this very 
remarkable fauna has been obtained. It is imbedded in fresh-water 
1 Tf this rate were to continue uniform, a change of inclination of ten degrees 
would be produced in 23,684 years. ‘The rate is, however, probably greater than 
this; for, since the ground slopes in a direction south of east, movements in this 
direction affect the inclination of the N.S. level, 
