4. Gaylussaccia resinosa, Torrey and Gray. Leaf in nodule at Green’s Creek. Abundant in New England and in Canada, also on Lake Huron and the Saskatchewan, according to Richardson ([Fig. 77]).

5. Populus balsamifera, Linn. Leaves and branches in nodules at Green’s Creek. This is by much the most common species, and its leaves are of small size, as if from trees growing in cold and exposed situations. The species is North American and Asiatic, and abounds in New England and Canada. It extends to the Arctic circle, and is abundant on the shores of the Great Slave Lake and on the McKenzie River, and according to Richardson constitutes much of the drift timber of the Arctic coast ([Fig. 78]).

Fig. 77.—Gaylussaccia resinosa. Pleistocene, Canada. Fig. 78.—Populus balsamifera. Pleistocene, Canada.

6. Thuja occidentalism Linn. Trunks and branches in the Leda clay at Montreal. This tree occurs in New England and Canada, and extends northward into the Hudson Bay territories. It is a northern though not arctic species in its geographical range. According to Lyell it occurs associated with the bones of Mastodon in New Jersey. From the great durability of its wood, it is one of the trees most likely to be preserved in aqueous deposits.

7. Potamogeton perfoliatus, Linn. Leaves and seeds in nodules at Green’s Creek. Inhabits streams of the Northern States and Canada, and according to Richardson extends to Great Slave Lake.

8. Potamogeton pusillus. Quantities of fragments which I refer to this species occur in nodules at Green’s Creek. They may possibly belong to a variety of P. hybridus which, together with P. natans, now grows in the river Ottawa, where it flows over the beds containing these fossils.

9. Cariceæ and Gramineæ. Fragments in nodules from Green’s Creek appear to belong to plants of these groups, but I cannot venture to determine their species.

10. Equisetum scirpoides, Michx. Fragments in nodules, Green’s Creek. This is a widely distributed species, occurring in the Northern States and Canada.

11. Fontinalis. In nodules at Green’s Creek there occur, somewhat plentifully, branches of a moss apparently of the genus Fontinalis.