234 ANCIENT EARTHAVORKS OF OHIO. 



below that point has been actually filhvl up. This would be 

 likely to take place since the banks, from being stripped of trees, 

 the roots of which protected them, have been extensively under- 

 mined and precipitated into the stream. The Colerain embank- 

 ment was probably a work of defence, as it commanded a penin- 

 sula formed by a bend in the river of tAVO miles in circumference. 

 It has been thrown up from a ditch on the outside, which, passing 

 through loam into the substratum of gravel, gives, in a transverse 

 section, unequivocal evidence of its artificial origin. PI. X, f. 2. 



The most interesting work confirmatory of the view taken, 

 namely, that the degradation of the surface has been very slow, is 

 on the Little Miami, about thirty miles from Cincinnati and about 

 six miles east of Lebanon, in Warren county, Ohio. This work 

 occupies a terrace on the left bank of the river, and two hundred 

 and thirty feet above its waters. The place is naturally a strong 

 one, being a peninsula, defended by two deep ravines which, origi- 

 nating on the east side near to each other, diverging and sweeping 

 around, enter the Miami, the one above and the other below. 

 The Miami itself, with its precipitous bank of t\vo hundred feet, 

 defends the western side. The ravines are occcupied by small 

 streams. Quite around this peninsula, on the very verge of the 

 ravine, has been raised an embankment of unusual height and 

 perfection. Meandering around the spurs and reentering to pass 

 the heads of the gullies, so winding is its course, that it required 

 one hundred and ninety-six straight lines to complete its survey. 

 The whole circuit of the work was between fom* and five miles. 

 The number of cubic yards of excavation Avas approximately 

 628,800. The embankment stood in many places twenty feet in 

 perpendicular height, and although composed of a tough diluvial 

 clay, without stone except in a few places, its outward slope was 

 so steep as from thirty-five to forty-three degrees. This work 

 presents no continuous ditch, but the earth for its construction 

 has been dug from convenient pits, which are still so deep as to 

 be filled with mud and water. Although I had brought out a 

 party of a do^en active young engineers from the Pleasant HiU 

 academy, and we had encamped upon the ground to expedite 

 our labors, we were still tAvo days in completing the survey, 

 which, with good instruments, we conducted with all possible 



