Some portions of this rock contain very perfect shells.

With respect to the vegetable productions of the district the _populus trepida_, or aspen, which thrives in moist situations, is perhaps the most abundant tree on the banks of the Saskatchawan, and is much prized as fire-wood, burning well when cut green.

The _populus balsamifera_, or taccamahac, called by the Crees _matheh meteos_, or ugly poplar, in allusion to its rough bark and naked stem, crowned in an aged state with a few distorted branches, is scarcely less plentiful.

It is an inferior fire-wood, and does not burn well, unless when cut in the spring, and dried during the summer; but it affords a great quantity of potash.

A decoction of its resinous buds has been sometimes used by the Indians with success in cases of _snow-blindness_, but its application to the inflamed eye produces much pain.