GLACIAL LAKE AEKONA. 373 



The Huron delta seems very flat to the eye but slopes gently toward its edge. The excep- 

 tional quality of its soil was noticed by Sherzer in his study of the surface features of Wayne 

 County. Upstream it consists of very coarse gravel and some sand, growing noticeably finer 

 toward the edge. Exposures in the central part show 5 or 6 feet of gravel. 



The special characteristic of tins soil, like that of the gravel belts that mark the wasked- 

 away Arkona ridges, is its stiffness or hardness. The gravel and sand do not make a light, 

 friable soil, like that of unmodified deltas, but one that is very stiff on account of the clay which 

 it contains. Clods are common and rather resistant. 



Some of the Arkona deltas show another peculiar modification due to submergence and the 

 work of storm waves. The most notable example is on the delta of the Huron 5 miles southeast 

 and east of Ypsilanti. For a width of about 6 miles along the shore the delta was built out into 

 the lake more than 2 miles beyond the general shore fine. After submergence, the storm waves. 

 of Lake Whittlesey running in toward the shore, struck the front of this delta and tore loose- 

 much of it, budding the material into a great, broad ridge 15 to 20 feet high and three or four 

 times as broad as the strongest ordinary beach ridge. The inner area of the delta is to the eye 

 a perfectly flat plain and is composed of gravel stiffened by a moderate admixture of clay. But 

 the whole front of the delta is bordered by great broad, smooth, gravel ridges, the strongest one 

 along the outer front with two or three weaker ones behind. These ridges correspond very 

 closely and in fact are continuous with the Arkona ridges, but are overgrown in their proportions. 

 The best example observed runs west through the south part of sees. 31 and 30, Van Buren 

 Township and is repeated less perfectly on the north side of Huron River. The same characters, 

 but not so strongly developed, may be seen at Milan and below Plymouth and Rochester. It 

 seems certain that these are forms produced by modification during submergence and are not 

 normal Arkona deltas nor normal unmodified Arkona beaches. They are much like the heavy 

 beach ridges which fringe the outer border or front of some of the deltas of Lake Whittlesey,, 

 notably those at Plymouth and below Ypsilanti, but they are so modified that they can no longer 

 be regarded as normal beach ridges. 



ARKONA BEACHES IN OHIO, PENNSYLVANIA, AND NEW YORK. 



In the summer of 1905 a month was spent by the writer, under the direction of Prof. T. C. 

 Chamberlin, studying the Arkona beaches in Ohio and farther east. Two Arkona ridges of 

 fairly good development, but with the usual modified characters, were found to extend from the 

 Ohio-Michigan hue 5 miles northwest of Sylvania, Ohio, to within 2 or 3 miles of Napoleon on 

 the north side of Maumee River, where they appear to fade out. South of Napoleon a sandy 

 gravelly coating on the till plain appears to be an Arkona delta of Maumee River. From 

 Napoleon eastward the investigation had the character of a rapid reconnaissance rather than of 

 a detafled study, the beaches being looked for only at intervals of 15 or 20 miles. Southeast of 

 Napoleon and eastward to the vicinity of Bradford the horizon at which the Arkona beaches are 

 supposed to occur is on an extremely flat clay plain, and in this interval no certain evidence of 

 the beaches was found, though some might be discovered by more detailed search. Farther 

 east, in the vicinity of Bellevue, the shore of Lake Arkona faced northwest and carried dunes. 

 The dune deposit is irregular and patchy, but it appears to mark the Arkona level, being about 

 700 feet above sea level and lying as elsewhere between the Whittlesey and Warren beaches. 

 Eastward to Cleveland and thence along the narrow bench at the base of the escarpment into 

 western New York the Arkona beaches ' are fairly strong locally, though broken and fragmen- 

 tary in places. In New York State the Arkona beaches seem to gain strength imperceptibly; 

 and after passing the Cattaraugus embayment and turning toward the north and northeast, 

 they become stronger and stronger and show progressively less modification. Near Hamburg, 

 Orchard Park, Spring Brook, and Manila the Arkona ridges are as strong and robust and as 

 little affected by modification subsequent to their original making as the beaches in the Black 

 River valley in Michigan. They keep on northeastward through Alden for a mile or two and 

 appear to end abruptly beneath gravelly deposits laid down in the valley of Ellicott Creek by 



1 Parts of this beach were traced by Mr. Leverett and are discussed in Mon. U. S. Geol. Survey, vol. 41, 1902, pp. 764 and 766. 



