From John Rae¹   21 February 1855

My Dear Sir

I believe the ice driven down the M^c Kenzie may be driven some hundred miles from that rivers mouth before it becomes wasted— The pressure of the water is so great that the ice is broken up when in some places (as along the banks where overflowings take place) fully six or 8 feet thick— Ice of this thickness would take a long while to dissolve, more particularly when a number of pieces are heaped one upon another as is often the case—

That seeds of plants should be thus conveyed long distances is extremely probable although I have no data by which to prove it—

What appears to me the most likely way in which the seeds of Arctic plants are so widely disseminated is by the winter gales of Northerly and North West winds— These sweep the ground and in many places denude it of snow and at the same time displace seeds and even portions of plants themselves— This may occur any time in winter, and the seeds so driven may get another “lift ” in the spring in the same way and may also be moved a long way farther, in the way you suggest— I have in hundreds of places seen ice forced sufficiently high on the land to afford an opportunity for the plants to vegetate when the ice thawed—

Now I have no proof of the above but having lived much on the banks of one or two of the large streams falling into Hudsons Bay, and also on the M^c Kenzie, and seeing large masses of ice drive down those streams for days and perhaps weeks after the main body of ice had disappeared far to seaward, I think it not unreasonable to suppose that some of these masses might go a long way before being broken up or melted—

I am far from thinking your question a simple one, on the contrary it would require long and close investigation to decide it with certainty—

Some unexpected bad news from the north obliges me to leave town tomorrow, but I contemplate being here again in a fortnight so that any other questions you may ask I shall be always most happy to reply to in the best manner I can—

Believe me | My Dear Sir | very truly yours | John Rae Charles Darwin Esq^re. | &c &c &c