
Per ae NT) 1X. 

(A) Note on the Plants, collected by Mr. G. M. Dawson, from the Lignite 
Tertiary Deposits, near the Forty-ninth Parallel. 
By J. W. Dawson, F.R:S. 
The specimens consist of leaves and other remains preserved in shale, and of 
silicified woods, mostly found loose ; but without doubt derived from the same forma- 
tions with the other remains. Vegetable structures also appear in some of the Lig- 
nites, and can be developed by the action of caustic potash, or nitric acid. 
I.—LEAVES ETC., IN SHALE.—(PLATE XV1.) 
The greater part of these are in a light grey or brownish shale, from Porcupine 
Creek, and the vicinity of Wood Mountain ; but another and somewhat distinct group 
of species occurs in dark grey shale from Great Valley, from beds believed to be very 
nearly on the same geological horizon with the others. The first and more important 
group, with reference to numbers and state of preservation, we may designate the 
the Porcupine Creek Group ; the second, the Great Valley Group. 
The plants of the first of these groups are for the most part identical with those 
found by the American Geologists in the Fort Union series, and which have been 
described by Prof. Newberry and Mr. Lesquereux. They are also similar to plants 
collected by Dr. Richardson in the Lignite series of the Mackenzie River, as described 
by Heer, and represented by specimens in the collection of the Geological Survey and 
of the University. They also approach very closely to the so-called Miocene floras 
of Alaska and Greenland, as described by Heer ; and in their facies and in several of 
their species, they coincide with the Miocene flora of Europe. 
If we were to regard the affinities of the plants merely, and to compare them 
with the Miocene of other countries, and also to consider the fact that several of the 
species are identical with those still living, and that the whole facies of the flora coin- 
cides with that of modern temperate America, little hesitation would be felt in as- 
signing the formation in which they occur to the Miocene period. On the other 
hand, when we consider the fact that the lower beds of this formation hold the 
remains of reptiles of Mesozoic type, that the beds pass downward into rocks holding 
- Baculites and Inocerami, and that a flora essentially similar is found associated with 
Cretaceous marine animal remains both in Dakota and in Vancouver’s Island, we 
should be inclined to assign them at least to the base of the Eocene. They have in 
fact been thus variously placed, and recently Lesquereux has attempted to sub-divide 
the beds of the corresponding rocks in the United States into a series of groups, 
ranging from the Cretaceous to the Miocene. 
