T02 Frank Carney 



two-thirds of the sheet's area, the Berea sandstone formation is 

 either on or very near the surface. Preglacial weathering of the 

 Berea cut it back towards Elyria, making a depression followed 

 now^ by the Black ri\er. This depression is confined northward, 

 and is bounded, by sandstone outcrops near Avon Center and Shef- 

 field Junction ; sexeral outliers of the Berea extend southwestward 

 from Sheffield Junction. For many miles south of this escarp- 

 ment the Berea sandstone has a very shallow covering of drift. 



Wherever a shoreline coincided with the outcropping Berea, 

 the waves produced a load of stand for transportation. Beach 

 ridges and other shore forms were constructed more quickly than 

 when the waves worked only on shale or on glacial drift. In every 

 case the most conspicuous beaches reflect this rock influence. A 

 similar influence is seen also in the islands, formed by outliers of 

 the Berea sandstone, and in barriers that were constructed in the 

 shallow water overlying outliers that did not form islands. 



THE MAUMEE SHORELINE 



At most points where this shoreline has been studied in Ohio, 

 it consists of two beach ridges, separated by a vertical difference 

 of ten to twenty feet; the upper shoreline has an altitude of about 

 770 feet. These two ridges generally are present in the Oberlin 

 sheet. 



A broad embayment characterized the Aiaumee shoreline in 

 the Oberlin quadrangle. This bay. during the higher Maumee 

 stage, extended about four miles southward from Elyria. 



Upper Maumee stage. — Commencing on the western edge of 

 the sheet, for nearly five miles I have indicated a single beach for 

 the Maumee stage. In this distance the shoreline is not very well 

 developed. The glacial drift does not appear ever to have been 

 thick here, and the outcropping shale did not furnish the waves 

 an abundant supply of material for shore structures. Nearly two 

 miles east of Amherst, at the highway leading directly north, I 

 liave mapped two ridges, but I l)elieve that this complexity repre- 

 sents cusp structures rather than distinct beaches. On the hypo- 

 thesis that the lower Maumee shoreline, in this distance of five 

 miles, did not dexeloji a A-ery sharp beach-ridge, it is possible that 

 weadiering has made its detection diflicult, and that closer study 

 might give a location to l)oth levels. 



Near the boundary between Amherst and Elyria townships 

 the Maumee shoreline tiu'ns directlv south, and thus continues to 



