252 ROLLIN T. CHAMBERLIN 



the western ice crept, but either did not leave any debris, or so little 

 that it has since been removed. In Wisconsin it occurs largely in 

 patches, partly because little or no drift was left in some localities, 

 and partly because of stream erosion. East of Osceola this glacier 

 actually reached the St. Croix moraine; from the north of the map 

 to within three miles of St. Croix Falls no gray drift was found on 

 the east side of the river, though striae interpreted as belonging to 

 the gray ice, and a few limestone pebbles, indicate that the Kewatin 

 glacier visited these parts. As this region was covered only by the 

 extreme edge of the Minnesota glacier, which seems to have been 

 thin, and not to have remained here long, it did not effect a great 

 change in the topography. Some of the hills of red drift were worn 

 down, and many of the depressions filled, but the covering of gray 

 drift is too scanty to mask entirely the old red topography. 



The gray terminal moraine. — While the red terminal moraines in 

 this region are all of the recessional type, though large and prom- 

 inent, the gray moraine is a limiting terminal marking the extreme 

 extension of the sheet, but it is the weakest and most obscure of all. 

 So far as .my knowledge goes, the gray terminal first appears at the 

 north within the quadrangle about half a mile east of the river, and 

 a mile north of St. Croix Falls, where it is very indistinct. North of 

 this, on account of the scarcity of gray drift, it has not been recognized. 

 From this point it runs slightly east of south for two miles, becoming 

 a more pronounced ridge ; but it cannot be traced beyond the great pit 

 near the railroad tracks, one mile southeast of St. Croix Falls station. 

 From the pit the boundary of the gray till- sheet swings sharply to 

 the west, and then southwest along the slopes of a high veneered rock 

 hill, until it is lost amid Keweenawan ledges, two and a half miles 

 south of Taylor's Falls. Farther south, however, at Dresser Junc- 

 tion, there is a hummocky ridge, though scarcely more than half a 

 mile long, piled up across the front of the great gap in the St. Croix 

 moraine. This is the best-developed portion of the gray moraine. 

 Considering the position of this strip, and the direction of the ridge 

 running from St. Croix Falls south to the great pit, it appears a plaus- 

 ible view that the ice-front at its maximum point stood along a line 

 connecting these morainic strips, approximately where the railroad 

 is today. However, no gray drift was found on the upper part of 



