Biology Reference
In-Depth Information
Figure 5.1 Pseudocycas
thomasii
(Bennettitales) from
the Early Cretaceous of West
Greenland. From Boyd 1998a.
Used with permission from
E. Schweizerbart'sche Verlags-
buchhandlung Science Pub-
lishers, Stuttgart (http://www
.schweizerbart.de).
from most modern forms, but some are similar to cycads, the Asian de-
ciduous gymnosperm tree
Ginkgo
, and angiosperm trees of the Betulaceae
(birch), Myricaceae (
Myrica
, or gale), and Ulmaceae (elm) families. Fossil
wood of palm is common, and other woods show poor to moderately devel-
oped growth rings. On Ellesmere Island, Campanian-Maestrichtian sedi-
ments and fossil assemblages from a coastal plain/mire habitat reveal active
volcanism, fl ooding, and occasional frost (Falcon-Lang et al. 2004).
Overall, across the high northern latitudes, Cretaceous vegetation con-
sisted of the relatively newly arrived angiosperms, competing with the ferns
and allied groups and with the gymnosperms. There was probably some
habitat differentiation into warmer and less climatically seasonal coastlands,
and cooler and more climatically seasonal inland and uplands. There was
also a mixture of elements that are either extinct or now found primarily in
