232 NATURAL SCIENCE [October 1898 
more closely to the higher Cretaceous floras, such as that of the 
Laramie. The Patoot series may perhaps be safely interpreted as 
constituting a palaeontological as well as sedimentary transition 
from the Atane series to the Tertiary. The thickness of the Atane 
and Patoot series (Senonian) is not less than 1300 feet and may 
considerably exceed this. 
TERTIARY AND LATER GEOLOGY OF W. GREENLAND 
Many plants from Atanikerdluk were referred by Heer to the 
Miocene, but are now generally admitted to be Oligocene, and 
Messrs White and Schuchert suggest that they may even be of 
Eocene age. They further remark that the distinction between the 
floras of Heer’s three Cretaceous series rests largely on minutiae of 
systematic description that cannot be upheld, a view that will 
doubtless be shared by most palaeobotanists. 
There is some evidence for Tertiary erosion west of Niakornat. 
After this the entire region was covered by a great number of super- 
imposed, approximately horizontal, non-columnar basalt beds of 
varying thickness and of great extent. Frequently 3000 feet of 
this basalt cap remains, while at Kilertinguak (6250 feet above 
tide) over 4000 feet is preserved. In certain regions numerous 
dikes intersect at varying angles the Cretaceous, Tertiary, and even 
the lower portion of the basalt cap, and are frequently found both 
forking and intersecting. Intruded basalts are not rare, especially 
in the Tertiary. The peridotite intrusive beds, about 350 feet 
thick, behind Kaersut, are probably of Tertiary age, as are also the 
other high intercalated basalts. At the time of the great elevation 
of the region, probably in the late Tertiary, the basalt cap, which, 
judged by the development on Unbekanntes Island, may have 
exceeded 7000 feet in thickness, most probably extended north- 
wards in an unbroken sheet from the south of Disko Island to 
beyond the Svartenhuk peninsula, a distance of 250 miles. 
The dissection of this great basalt sheet, the development of the 
Vaigat, the Umanak fiordal system, the isolation of Disko—in fact, 
approximately the present land topography of this coast—-were 
accomplished at a much greater elevation during Pleistocene time. 
Evidence of post-Pleistocene subsidence, with Arctic climatic condi- 
tions, is found in the presence of recent Arctic marine shells occur- 
ring in terraces at an elevation of from 100 to 150 feet above tide. 
In the old crystalline region, much farther south, the terracing is 
said to extend to 300 feet above tide. The extent of the more 
recent uplift is not known, since the retreat of glaciers, the inun- 
dation of ancient dwelling-sites, and the records of tide-gauges 
point to present downward movement observable within historical 
time. 
