232 The American Geologist. April, i899 
part, to subsequent movements that tlie chalk also has sufifered 
( Ann. des Mines, Jan., 1893, 36). 
The different parts of the ancient mountains of the Arden- 
nes overlapped by Triassic, Jurassic, Liassic, Cretaceous, and 
Tertiary formations, were doubtless exposed to denudation 
for different periods of time, and successively submerged in 
encroaching seas: it is quite possible that the dissected uplands 
of today were peneplained at a distinctly later date than was 
the floor beneath the Jurassic strata, and that the relation of 
the two is similar to the relation stated by Darton for the two 
l)arts (AB and BE, Fig. i) of the ancient rocks of the Pied- 
mont belt in Virginia. French writers do not seem to have 
occupied themselves especially with this question, either in 
the Ardennes or in the Central plateau. But on the other 
hand there seems to be no question that the stratigraphy of 
both the marine and the terrestrial deposits proves the exist- 
ence in northern France of a denuded surface of small relief, 
whose larger part is now buried, and whose smaller part is 
elevated and more or less dissected. 
Bohemia offers another remarkably good example for cita- 
tion, as summarized by Penck and here freely rendered. A 
great mountain range once rose there, probably reaching an 
altitude of 5,000 meters. It was Avorn down to a comparative- 
ly even lowland before the incursion of the Cretaceous sea, b} 
whose deposits it is now thinly covered, for freshwater forma- 
tions are everywhere found under the Cretaceous strata. This 
relation is repeated in many other parts of Europe, especially 
where truncated old mountains are found. Terrestrial forma- 
tions are their first cover, and upon these rest the later marine 
deposits. It follows from this that the truncated mountains 
of Europe were not denuded by the surf of ancient seas, eating 
into their hights and gradually wearing them away; for before 
the sea rolled over the old mountains they were already laid 
low and covered with terrestrial formations (Ueber Denuda- 
tion der Erdoberflache, A'ienna, 1887, 23, 24). 
While it may be true that there are to-day no extensive 
peneplains still standing close to the sea level with respect to 
which they were denuded, the examples given in this and in 
the preceding section seem to me to prove that the earth con- 
tains many appioximations to the peneplain condition, inas- 
