Geolo(iy of the St. Croix Dalles. — Berkey. B-il) 
Maps. Two maps have been drawn in illus^tration of the 
topography unci geolog}'^ of the area. The first includes the 
whole district of sixty square miles (see Plate XX, map No. I) 
while the other, comprising four square miles and including 
the greater part of the villages of Taylor's Falls and St. Croix 
Falls, represents the immediate vicinity of the Upper Dalles on 
an enlarged scale and with greater accuracy of detail (see Plate 
XXI, map No. II). Figure 1 is an outline map representing the 
location of the Saint Croix Dalles Area. 
Lakes. The lakes occurring in the district are of two 
kinds: 1st, Glacial lakes; 2d, River lakes. In the first class 
there are two minor groups: 
1st. Those which occupy many of the larger kettles of the 
glacial moraine which borders the northern and eastern sides 
of the district. These lakes* partly fill the larger and more 
favorably situated of the numerous depressions of the moraine 
and are doubtless much less abundant now than formerly. 
Many of the kettles may be seen in crossing the moraine at 
almost any point. Most of these lakes have no outlet, al- 
though it is probably these very lakes that feed so constantly 
the springs along the river banks nearly 500 feet lower down. 
The largest of these lakes are East lake, Poplar lake and Rock 
lake. All show a gradual subsidence. 
2d. Those which remain from the rather extensive marshes 
or sloughs of the belt of till occupying a part of T. 34 N., R. 
19 W. These lakes are now very shallow, and compared with 
their former extent, have almost disappeared. They once had 
outlet to the St. Croix river across the flat meadow land 
stretching northward and southward, but at the present time 
they are stagnant and muddy. Colby lake, with the four or 
five small lakes near it, are the representatives of this class. 
Under River lakes have been included those now occupying 
abandoned channels of the St. Croix river. All of these lakes 
lie close to the present channel of the river, and most of them 
are directly connected with it and lie at the same level. The 
most prominent one is Thaxter lake in Sec. 86, T. 34 N., R. 19 
W. It occupies a portion of the channel worn by a part of 
the river previous to tlie formation of the 750-foot terrace. A 
small swampy pond not deserving of the name of lake is 
*Geology of Wisconsin, vol. Ill, 1880, p. 374. 
