The Geological History of PlantsDawson, John William, Sir
Science
The Geological History of Plants
Dawson, John William, Sir
Paleobotany
The fossil plants collected by Dr. G. M. Dawson in the eastern area were
noticed by the author in an appendix to Dr. Dawson's report on the 49th
parallel, in 1875, and a collection subsequently made by Dr. Selwyn
was described in the "Report of the Geological Survey of Canada" for
1879-'80. Those of the western area, and especially collections made by
myself near Calgary in 1883, and by officers of the Geological Survey in
1884, have been described in the "Transactions of the Royal Society of
Canada" vols. iii. and iv.
In studying these fossil plants, I have found that there is a close
correspondence between those of the Lower and Upper Laramie in the two
areas above referred to respectively, and that the flora of the Lower
Laramie is somewhat distinct from that of the Upper, the former being
especially rich in certain aquatic plants, and the latter much more
copious on the whole, and much more rich in remains of forest-trees. This
is, however, possibly an effect rather of local conditions than of any
considerable change in the flora, since some Upper Laramie forms recur
as low as the Belly River series of the Cretaceous, which is believed on
stratigraphical grounds to be considerably older than the Lower Laramie.
With reference to the correlation of these beds with those of the United
States, some difficulty has arisen from the tendency of palæobotanists
to refer the plants of the Upper Laramie to the Miocene age, although
in the reports of Mr. Clarence King, the late director of the United
States Geological Survey, these beds are classed, on the evidence of
stratigraphy and animal fossils, as Upper Cretaceous. More recently,
however, and partly perhaps in consequence of the views maintained by the
writer since 1875, some change of opinion has occurred, and Dr. Newberry
and Mr. Lesquereux seem now inclined to admit that what in Canada we
recognise as Upper Laramie is really Eocene, and the Lower Laramie
either Cretaceous or a transition group between this and the Eocene. In
a recent paper [DV] Dr. Newberry gives a comparative table, in which he
correlates the Lower Laramie with the Upper Cretaceous of Vancouver
Island and the Faxoe and Maestricht beds of Europe, while he regards the
Upper Laramie as equivalent to European Eocene. Except in so far as the
equivalence of the Lower Laramie and Vancouver Island beds is concerned,
this corresponds very nearly with the conclusions of the writer in a
paper published last year[DW]--namely, that we must either regard the
Laramie as a transition Cretaceo-Eocene group, or must institute our
line of separation in the Willow Creek or Middle Laramie division, which
has, however, as yet afforded no fossil plants. I doubt, however, the
equivalence of the Vancouver beds and the Lower Laramie, except perhaps
in so far as the upper member of the former is concerned. I have also to
observe that in the latest report of Mr. Lesquereux he still seems to
Public-domain text, read in full here on John Shaqi.
Reviews
Reviews
No reviews yet
Be the first to share your thoughts on this work.
Elsewhere in the archive
Join the Discussion
Join the discussion
Sign in to leave a comment or review.
Sign InorCreate an account