[TYRRELL] PRESIDENTIAL ADDRESS 23 
Thirty miles below the mouth of Fox river, Hayes river is joined 
by the Shamattawa flowing from the southeast in a still wider valley, 
and from the junction of these two streams it turns and flows north- 
ward for fifty miles to its mouth in Hudson Bay. Like in its upper 
portions it does not here anywhere fill the bottom of its valley, but 
swings from bank to bank, first washing the foot of a steep naked 
cliff on one side and then the foot of a similar cliff on the other side, 
with alluvial flats opposite these cliffs. Occasionally the river would 
appear to have altered its course by cutting out a new channel through 
one of these alluvial flats, probably on account of the formation of a 
dam of broken ice in the spring across the old channel, in which case 
two channels may remain after the disappearance of the ice dam with 
an island between them that was previously a part of the alluvial 
flat. At the naked cliffs on the outer sides of the curves of the stream 
sand and clay continue to slide, or to be washed down, into the water 
by which it is carried along for some distance until it is dropped either 
to the bottom or on points or islands in the stream. 
In its lower portion the valley of Nelson river differs in some 
important particulars from that of the Hayes. Like in the valley 
of the latter stream the banks are steep and often precipitous, but 
unlike it the river fills the valley from bank to bank not only in the 
tidal portion at its mouth, but as far as I could see upwards from 
the summit of Gillam Island. No bottom lands of any appreciable 
extent could be seen and there are no terraces along the sides of the 
valley, for the river above the head of tide water is at present actively 
engaged in undercutting both of its banks, and in deepening its chan- 
nel from side to side. It is true that there are terraces at the mouth 
of Seal Creek and other tributaries, and at the north end of Gillam 
Island, twenty-five feet above tide water and apparently of the age 
of the Mission Beach, but they have only been preserved in protected 
localities where the river has not been able to reach them and to cut 
them away. Doubtless similar terraces existed at many places along 
the sides of the valley but they have been washed away. 
Gillam and Seal Islands, which lie just at the head of tide water 
in Nelson river, also differ from any of the islands in Hayes river, 
in that they are composed entirely of till, and rise to the full height 
of the adjoining plain from which they have been cut off or separated 
by the river, doubtless assisted in the first place by a small stream 
which joins the main river immediately to the west of them. 
The sizes of the two valleys are not at all proportioned to the sizes 
of the two streams which flow in them, for while Hayes river is only 
about one-eighth of the size of Nelson river the valley in which it 
flows is the larger of the two. 
