604 GEOLOGY OF OHIO. 



Very little definiteness is apparent in the plan of their distribution, but 

 they are most prevalent in the north-eastern, central, and south-western 

 portion of the county, or along a line passing through the centre of the 

 county parallel to the water-shed. Between Greenville and Richmond, 

 along the Pittsburg, Cincinnati and St. Louis Railroad, they are unusually 

 clustered, and are worked by that company in many points. Sometimes 

 they are single and isolated, and at others lie in groups. If, as we 

 must certainly concede, they have been formed by the action of water, 

 these two facts, namely, their shape and distribution, would rather lead 

 us to suppose their source and cause from the north-west, or at right 

 angles to the direction of the divide. 



Moreover, in the relation of the kames to the surrounding soil, there is 

 something very peculiar. It is frequently the case that in the midst of 

 a low, flat, peat bog or black bottom land rise up one, and sometimes 

 several, of these picturesque gravel knolls. We would naturally look for 

 them o\ er a stony, hard-pan region, where the gradation of material is 

 very slight, and where the conditions of both characters of soil seem con- 

 genial and similar ; but when we meet with them in the contrast men- 

 tioned above we are compelled to acknowledge it as something singular 

 and perplexing. But to me it appears this fact in the study of their 

 origin would urge us to regard them as due to local and modern causes, 

 as they evidently must have been formed just where they are, and by 

 causes and at times entirely distinct from those of the surrounding for- 

 mations. 



Here, as elsewhere in western Ohio, they are composed of a mass of 

 sand and gravel, intermingled with a small quantity of yellow clay. The 

 color of the materia' is, for the most part, yellow, like that of the clay, 

 with occasionally veins and streaks of blue running through it, but 

 frequently from the presence of iron and sulphur it is of a reddish brown 

 color. In most places the sand and gravel are finely assorted and strati- 

 fied, in the others mingled and unstratified, and almost universally depos- 

 ited in wedge-like layers, interlocking one with another. The absence 

 of .large bowlders, and the roundness and smoothness of the pebbles, at 

 once point to water as a sufficiently potent and probable agent, and the 

 above facts as to their character, stratification, form of layers, plan of 

 stratification, etc., plainly appears to indicate the frequent changing or 

 confliction of small but in many cases forcible currents of water. 



The pebbles are mostly of a uniform size, ranging from one-half to two 

 and three inches in diameter, and are always well worn and rounded, 

 very rarely bearing any glacial scratches. Sometimes, however, quite 

 massive bowlders are found imbedded in them. Flint, granite, syenite, 



