Geoloijy of the St. Croix Dalles. — Berkeij. 365 
This 300-f()ot valley, from one-fourth to one-half a mile 
wide, extending back among morainic ridges for several miles, 
and showing undisturbed terminal accumulations almost to 
the bottom, constitutes a somewhat unique feature in the sur- 
face geology of the district. It probably lies in the direction 
of movement of the latest ice advance, and is partially due to 
glacier erosion of an older drainage course. 
//. Effect of Glacial Action upon Earlier Formation.^. The 
glacial action left distinct marks upon both the igneous and 
the sedimentary rocks. On the diabase the effect is much 
more easily observed at this time, although the action was 
very much more effective on the sedimentary rocks. Glacial 
strife, smoothing of exposed surfaces, the breaking down of 
ragged cliffs, tluting and glacier erosion can be seen. All 
these except the last are more successfully preserved and 
therefore more readily seen on the igneous outcrops. 
Glacial strije are not found at every outcrop, although 
one or more of the above Jiientioned evidences of glacial ac- 
tion are to be seen at any extensive exposure. Those showing 
striae most plainly and abundantly with their bearings are the 
following; 
1. N. E. I4, N. E. I4, Sec. 1, T. 31 N., R. 19 W. 
Near road — few striae bear S. to S. E. 
West side of outcrop — strias bear almost E. and W., as an averKge di- 
rection. Of the variable ones, the greater number run N. E. and S. W. 
angle of variation nearly 90 degrees. 
Most of the strite are along the extreme western border of the outcrop. 
Of those noted the majority had a direction N. of E. to S. of W., be- 
tween 15 and 20 degrees, a few were found from W. of N. to E. of S. 
jtbout 20 degrees, and still others were E. and W. 
2. S. W. I4, N. W. L4, Sec. 6, T. .34 N., R. 18 W. 
West slope of outcrop — strias found only on the smooth, close grained 
I)ortion of the exposure. They bear E. and W., also N. of W. to S. of E. 
3. N. W. I4, Sec. 5, T..33, N., K. 18 W. 
Markings on the very smooth polished surfaces of the diabases of the 
old channel from which the soil has lieen removed l)y the building of 
the M. St. P. & S. Ste. M. railway, bear almost X. and S. These mark- 
ings may have other origin. 
4. Sec. .31, T. .34 N. R. 18 W., near the center of the south half of the 
section, in the public road, are some low, evenly j)oIished exposures of 
diabase on which markings occur. 
5. In the village of Taylor's Falls, near the Swedish church on the 
highest exposed portion of the igneous rocks, glacial markings may lie 
