392 THE GLACIAL LAKE AGASSIZ. 



the Norcross shores on the eastern side of "the mountains" he mostly 

 within a half mile to 1 mile distant from the highest Herman shore. Upon 

 this somewhat steep slope, intersected by numerous ravines, neither the 

 Herman shores nor the Norcross shores are so distinctly traceable as usual, 

 either by beach deposits or by lines of erosion. 



From the northern end of "the mountains," near Edinburg, the Nor- 

 cross shore-lines run north-northwestward, passing about 2 miles east of 

 Gardar, less than a mile west of the little village of Mountain, and about 

 1.^ miles east of Young post-oflfice. At the locality last named the upper 

 Norcross shore lies about a third of a mile east of the lowest Herman 

 beach, and is marked by a ridge of gravel and sand 10 to 20 rods wide, 

 with a depression of 1 to 4 feet on its west side and a descent of about 

 6 feet in a few rods to the east. Its crest has an elevation of 1,143 to 

 1,145 feet, being 30 feet lower than the adjacent Herman ridge. 



The outer border of the plateau of the Pembina delta, forming the 

 "first Pembina Mountain," was the Norcross shore of Lake Agassiz. After 

 the Herman stages of this lake all its lower levels with southward outflow 

 washed the front of the Pembina delta, carrying away nuich of this dejjosit 

 southward and eastward, and producing the steep escarpment, mostl}- 100 

 to 175 feet high, by which it is bounded on the east. 



On the more gradually sloping northern edge of this delta, 2 to 4 miles 

 west of Walhalla, a beach formed during the lower Norcross stage passes 

 from east-southeast to west-northwest. In the north half of section 23, 

 township 163, range 57, where its crest has an elevation of 1,135 to 1,140 

 feet, it is a broad, low ridge, chiefly of sand, with fine gravel, containing 

 pebbles up to 1 or 2 inches in diameter. Most of the gravel is derived 

 from the Cretaceous shale of the Pembina Mountain, but a part is of lime- 

 stone and crystalline Archean rocks. A depression of 5 or 6 feet, 15 to 20 

 rods wide, lies on the southern side of the beach, away from the lake; and 

 its northern side falls off into the lacustrine area with a gentle slope. 



Two miles farther northwest the Norcross shore-lines, with the entire 

 Herman series, leaving the Pembina delta, sweep into the great Cretaceous 

 escarpment of the second Pembina Mountain, with which thej^ coincide 

 through several miles northward, crossing the international boundary. 



