210 The American Geologist. October, i898 
which a small stream escapes into the very narrow and 
crooked upper channel of the southern portion. The descent 
from Fish lake is very rapid, and is strewn with boulders of 
large size. After passing a very deep and narrow pool three- 
fourths of a mile long, into which the brook sinks, the valley 
opens out between limestone blufifs and drift terraces, and ends 
abrujitlv in a cul de sac at the head of Johnson creek, the fur- 
ther continuation, whether southward or south-eastward, be- 
ing now completely filled." With regard to this alternative, 
I should unhesitatingly say that the preglacial drainage was 
through Johnson creek. Any one approaching the middle 
portion of the valley occupied by this little creek cannot but 
be impressed by its depth and width, as compared with the 
insignificant stream which drains it. It is, in fact, almost a 
coulee. In spite of nature's efforts to efface the record, this 
explanation is confirmed by a study of the derivation of the 
water which supplies Johnson's creek. The drainage of Fish 
lake is absorbed in the limestone belt, as indicated by the 
(juotation from Bailey Willis ; but a small stream called Scotch 
creek, which drains from the north-west, comes over the west- 
ern terrace-wall of the Cul de sac through a slight notch, and 
is absorbed by the gravel before reaching the floor. This 
stream reappears a half mile or so east of the eastern ram- 
part of the cul de sac, and is there called Johnson creek. The 
lower part of this Johnson creek coulee is choked effectually 
by the great terrace of the Okanogan, so that the mouth of 
the old valley cannot be determined. Upon the retreat of the 
glacier, the lower end of the old Similkameen valley terminat- 
ing in the cul de sac, became filled with water. The lake 
thus formed was drained, not by the clearing away of the ob- 
structing drift, but by a narrow defile cut in the solid granite, 
through which one may now pass horseback into Johnson 
creek. (See diagram No. 2.) 
The drama thus enacted in the case of the Similkameen 
was reprodticed on a smaller scale and in a simpler form a 
few miles south at Spring coulee. This name is applied to the 
lower end of the Salmon creek valley, below the point where 
the stream turns sharply to quit the valley by a narrow gorge 
running due east. So qtiickly and almost imperceptibly is 
this movement accomplished that in coming down the valley 
