GLACIAL FEATURES OF ST. CROIX DALLES REGION 255 



Franconia station for instance, are comparatively gentle, but the 

 Minnesota bank is a steep cliff of Cambrian sedimentaries. A well- 

 developed channel, nearly parallel to the present course and about 

 one mile east of it, can be followed from the bend in the river at the 

 interstate park in Taylor's Falls to Osceola, where it joins the St. 

 Croix today just below Eagle Point. It is not difficult to find the 

 points at which this course was abandoned in the migratory process 

 — first two miles north-northeast of Osceola at a barrier of Kewee- 

 nawan, next two and a half miles farther upstream at a similar 

 obstacle, again at Thaxter Lake, and lastly at the elbow near Taylor's 

 Falls, where, finding a deep rock fissure, running northeast and 

 southwest, more in line with the new course of the stream below, the 

 opportunity was taken to readjust itself. Some readjustment is 

 evident also above the Dalles in the immediate vicinity of the town of 

 Taylor's Falls. 



Terraces. — Objections based chiefly upon the depth of the gorge 

 at the Dalles, and an assumed slowness of erosion through the com- 

 pact igneous rock, have been raised against considering the canyon 

 to be the work of the St. Croix since the glacial epoch. By Dr. 

 Berkey it has been referred to postglacial erosion. That this is so 

 is evident from a number of considerations. While the river occupied 

 the earlier channel just described, which was long after the ice with- 

 drew, it was cutting the rock barrier of the Dalles at 850 feet, more 

 than 150 feet above the stream-level at this point today. The por- 

 tion of the Dalles below the bend is still younger. But perhaps the 

 most conclusive and neatest bit of evidence is that furnished by the 

 terraces. 



Well-defined alluvial terraces line both banks of the St. Croix 

 above the Dalles, though there are none corresponding to them below 

 the bend in the river, and most of them gradually disappear a few 

 miles upstream. On the Wisconsin side the best benches are at 

 725 feet, 780 feet, and 810 feet levels; while in Minnesota the most 

 prominent are at 750 feet and 920 feet. There are some correspond- 

 encies between the two banks, but, in general, where there are exten- 

 sive flats on one side, the stream has swept away those opposite. The 

 750 and 920-foot terraces have small tallying benches across in Wis- 

 consin; but, the 725 and 810-foot flats are not to be found in Taylor's 



