INNER BORDER OF THE MIAMI LOBE. 381 



Dayton, 4 miles southeast of, in Beavertown quarries' S. 27° E. 



Liberty, 1 mile northeast of, on west bluff of Great Miami. _ S. 28° E. 



Liberty, 3 miles north of S. 28° E. 



Near West Milton, east bluff of Stillwater River S. 30° E. 



Gard's quarry, near Greenville - S. 5° W. 



Weavers station, Darke County - _ _ S. 5° W. 



INNER BORDER PHENOMENA. 



The district lying between this morainic system and the next moraine 

 to the nortli varies in width from 20 miles in the axis to a narrow neck with 

 a width of 5 miles or less near the borders of the lobe. It has throtighont 

 nearly its entire extent a very smooth surface. Along poi'tions of the 

 valleys, however, a few drift knolls of large size occur. The valley of 

 Mosquito Creek, which enters the Grreat Miami near Sidney, contains 

 several very sharp knolls 50 to 75 feet high; smaller ones are found in the 

 Miami Valley in the vicinity of Pi qua and between Piqua and Troy, and 

 there are other belts along tributaries of White River in Indiana. These 

 valley knolls form chains nearly at right angles with the course of the 

 moraine, and since thej are comprised largely of gravel it is thought that 

 tliey may have been formed by subglacial streams in their passage toward 

 the ice margin, and are, perhaps, to be classed as imperfect eskers. 



The surface of the upland, as remarked a^ove, is liberally strewn with 

 bowlders, and in places they form a conspicuous feature. The drift consists 

 largel}^ of till, and owing to the iri-egularities of the underlying rock 

 surface presents much variation in thickness, as shown below. 



The gas-well boring at Port Jefferson, in the Great Miami Valley, 5 

 miles above Sidney, penetrated about 300 feet of drift, but in the same 

 valley, from Sidney southward, rock exposures are numerous up to a level 

 within 50 or 75 feet of the bordering uplands. At Piqua there are quarries 

 in the valley, but a well at Mr. Wiley's, IJ miles north of the city, extends 

 to a level nearly 150 feet below the river bed without reaching rock, and 

 one at Joseph Sawyer's, on the bluff in the west part of the city, strikes 

 rock at a level fully 100 feet below the river bed. The well driller, J. M. 

 Stoker, of Piqua, reports that Wiley's well was in gravelly material for 

 about 30 feet, beneath which 140 feet of blue till was penetrated. In 

 Sawyer's well 8 or 10 feet of yellow till was succeeded by about 20 feet 



'The main bearing is S. 26° E. Orton's map. Geology of Ohio, Vol. I, p. 413, indicates strise in 

 that vicinity bearing S. 18° E. 



^Geology of Ohio, Vol. Ill, p. 501. 



