180 Wisconsin Academy of Sciences, Arts and Letters. 



Passing south about a mile we find the beach well defined in the north- 



■west part of Sec. 28, of this township on the south side of Salt Creek, It 

 is here a beach ridge composed of sand and gravel, and rises 10 — 12 feet 

 ^above the border of the plain on the east. The beach line is 30 — 40 rods 

 ^vide, and extends nearly one mile south from Salt Creek when the gravel 

 disappears, and a sea clifi: marks the continuation of the shore. The bank 

 ridge is excavated about 40 rods from the north end in a similar way to 

 that at Haas's pit; the excavation being from the east side of the beach 

 west nearly to the outer slope. The excavation is 12—14 feet deep in the 

 deepest part, and reveals a series of beds dipping slightly toward the east. 

 The upper 5 — 6 feet is a brown-stained gravel. The lower portion is a fine 

 gravel with sandy portions almost free from gravel. These sandy portions 

 are not so calcareous as glacial sands. A slight efifervescence Avas obtained 

 in but one or two tests, out of a dozen or more. The gravel is made up of 

 worn pebbles comprising nearly every class found in the drift of the vicin- 

 ity. There is not such a predominance of limestone pebbles as in the 

 kaves of the neighboring moraines. The nature of the gravel is very simi- 

 lar in Haas's gravel pit to that in the one just described. 



A sea cliff passes south from the beach ridge just described, through La 

 Grange. At the point where it is crossed by the C, B. & Q. Ry. its base is 

 46 and its top 64 feet above Lake Michigan. This cliff continues in a south- 

 easterly course from La Grange to the west border of the Des Plaines 

 river valley, having a height of 10 — 15 feet throughout the greater part of 

 the course. It swings down the river and becomes a part of its bluff — 

 from a point almost directly west from the village of Summit, near the 

 corners of Sees. 10, 11, 14 and 15, Tp. 38, R. XII E. 



Before continuing our discription of the distribution of the upper beach 

 it will be necessary to say a word respecting the outlets of Lake Michigan at 

 that time — since the beach lines are open opposite these outlets. There were 

 two channels of discharge into the Des Plaines valley. The most northerly 

 one had its western border, as stated above, about two miles west of Sum- 

 mit, and its eastern border was about three miles south from Summit, where 

 the river enters the Valparaiso moraine. Between these points the water 

 from the lake entered the channel now occupied by the Des Plaines river. 



Another avenue of discharge into this valley was through what is known as 

 " the sag," a low belt of marshy land about one-half mile in width, which 

 passes almost centrally through Tp. 37 N. , R. XII E, , from east to west, and 

 opens into the Des Plaines valley in Sec. 14, Tp. 37, R. XI E., at Say 

 Bridge Station. Between these two outlets is a prominent portion of the 

 Valparaiso moraine whose base shows evidence on all sides that it was 

 washed by the waters of the lake, the rise from the plain on the east being 

 nearly as abrupt as the bluff of the Des Plaines river on the west or the 

 border of the sag on the south. The sea cliff which was formed around 

 this moraine is flanked occasionally by gravel and sand deposits similar to 

 those found farther north along the sea cliff which was cat in the plain. 



