79 
appears, rather, to be a change involving a period of at least several years, 
and is possibly recurrent according to some cyclic differences in the water 
levels of the river in this district. 
Slough and Wet Meadow Vegetation 
Elements of slough and wet meadow vegetation have already been 
mentioned as occurring in the shallow, relatively undrained depressions on 
local river flood-plains and in similar situations on delta plains. They are 
very closely allied to the earlier stages of development in the delta vegeta- 
tion, but differ from these largely because they are situated on smaller 
bodies of water where wave action is little felt. They occur chiefly in and 
around small ponds isolated from the larger lakes in the deltas and in 
the abandoned channels of meandering streams. Both types of terrain 
occur in all states of development, and as a result it is possible to find 
slough vegetations in many conditions, ranging from floating aquatic plants 
to something approaching the mesophvtic forests. The general arrange- 
ment and contents of the associations differ little from those situations in 
the uplands of the park, but in none of those areas is there so complete a 
series to show the stages of development. 
Detailed studies of these floras have been made at the Government Hay 
Camp, along Murdock creek at about latitude 59° 14', in the sloughs on 
the west side of Slave river at the 30th base line, and in Cree (Mamawi) 
creek. These will be used for the following discussion in the order of their 
increasing mesophytism. 
An inspection of the maps of the 30th base line and Hay Camp areas 
(Figures 14, 13) gives some knowledge of the topographic history involved. 
At the 30th base line the small, ponded creek that flows in a half circle at 
the outer edge of the meadow district has obviously had a series of earlier, 
straighter channels that are now represented by the sloughs. Although its 
course has not been closely examined, the topographic features of the coun- 
try indicate that the creek was once a channel of Peace river, either by 
itself or as a branch of the present Scow channel. The general lowering of 
the rivers and the opening of new drainage lines has caused it to be aban- 
doned and to form a series of sloughs that represent late meanders. Mur- 
dock Creek valley gives the impression of having been, also, a former channel 
of the Peace, and to have had a much stronger flow of water in compara- 
tively recent time. The present crooked stream lies between long sloughs 
that are quite straight and must have carried parts of a large river. 
Hay Camp meadow differs from most abandoned channel sloughs in 
being nearly as wide as it is long. The lowland is here separated from the 
back country by a definite escarpment or bluff which may be followed 
around the w r est side of the small drainage stream and then through' a tim- 
bered area to the river above the rocky point. This bluff evidently w r as the 
former bank of the river w T hen the latter covered the entire Hay Camp dist- 
trict and w r as obstructed by granite islands that are now seen as low hills 
above the region south of the meadows. It seems clear that these islands 
formed the nucleus of a large area of sand and mud-bars which eventually 
turned the stream entirely to the eastward into its present course. The 
timbered district that lies between the meadow and the granite hills is 
91903 — 6 $ 
