GLACIAL LAKE ARKONA. 371 



ill-defined belts of gravel or gravelly soil which mark the former position of such ridges. In 

 general the first belt is the faintest, the second is slightly stronger, and the third is the strongest 

 of the three, being in some places easily recognized as a distinct ridge. This is what would be 

 expected if their modification was due to the passage of storm waves ever them, for naturally the 

 most deeply submerged ridge would be the least modified. 



In order to trace these ridges and make sure of their continuity as separate individuals it 

 was necessary to go over part of the ground where they occur very thoroughly. The beaches 

 were studied with particular care as to details in the interval between Spring Hill and Richmond 

 and again at several places farther southwest. In some places no definite beach ridge nor other 

 feature that suggested wave action was seen for 4 or 5 miles, but generally a careful examination 

 of the shallow sections exposed along the stream banks or roadsides revealed the gravel belts which 

 mark the former position of the beach ridges. In a very few places even this slight evidence 

 failed, and nothing at all representing the beach was seen. However, where all else was lacking, 

 a faintly ridged strip of ground 10 to 30 rods wide, distinctly more gravelly than the flatter 

 intervening areas and decidedly more gravelly than is characteristic of the till of the region, 

 was nearly always found. The beaches were studied with particular care in Kenokee, Wales, 

 Columbus, and Richmond townships. In Wales and Kenokee townships excursions on foot 

 and an examination of the soil showed distinctly three gravelly belts, in places a foot or two 

 higher than the adjacent ground, but scarcely perceptible to the eye as ridges. • In driving, 

 however, these belts might easily be passed unnoticed, even by those who have had extensive 

 experience in the study of shore-line features. This shows to what an extent their physical 

 expression has been destroyed. 



The finding of such indefinite features in one locality, or in several widely separated localities, 

 could hardly be accepted as proof of the former existence of the beaches along these fines. 

 But when the study on foot was carried over a wide area it was found that the gravel belts, are 

 not only distinct from each other, but that they run continuously across the country with 

 uniform relations to the other beaches and with uniform vertical intervals between them. In 

 these townships measurements of their altitudes show that they rise toward the northeast at 

 the same rate as the Whittlesey beach (about 1 foot a mile). Between these belts the soil is 

 distinctly less gravelly. 



These gravel belts were followed almost continuously from the vicinity of Lenox and Rich- 

 mond northward into the Black River valley before it was known that there were any Arkona 

 beaches in that valley. Their development into three robust, unmodified beach ridges north of 

 Spring Hill was not foreseen and can hardly be regarded in any other light than as a remarkable 

 confirmation of the growing belief that the three gravel belts were in reality the remains of grav- 

 elly beach ridges which had been washed away and almost entirely obliterated by the over- 

 sweeping seas of Lake Whittlesey. 



TEXTURE. 



The most peculiar characteristic of the gravel belts — noted in detail in Kenokee and Wales 

 townships but generally characteristic of the modified Arkona beaches — is their stiff clayey 

 quality. Unlike other beaches, which are sandy or gravelly and rather loose in texture, the soil 

 of these gravel belts is very stiff and forms clods that endure for a long time. Only their con- 

 tinuation for miles across the country, their persistent levels, and their final mergence into the 

 strong ridges of the Black River valley make it certain that even though they are so impreg- 

 nated with clay and form so firm a surface underfoot they are nevertheless the remaining basal 

 parts of beach ridges. 



The composition of these gravelly belts, however, is not that of the original Arkona beaches. 

 It results from the infiltration of fine clay into the remains of the beaches after their upper parts 

 had been washed away by oversweeping storm waves of Lake Whittlesey. If the depth of water 

 over the Arkona ridges during the time of Lake Whittlesey be considered, it seems certain that 

 the washing away of the gravelly ridges was accomplished mainly by oscillating movements of 

 the water on the lake bottom. The oscillating water was evidently able to move pebbles of con- 



