292 ! GEOLOGY OF OHi0. 
south it is wsually bordered by irregular, billowy dures of sard—the 
ridge, apparently, formed by’ the waves, the dunes by the wind. Pre- 
eisely the same results are now produced by the combined action of the 
waves and wind where low, swampy land extends to the lake, and the 
shore is bordered by a sand beach. 
The following section, near the Norwalk waterworks! will exhibit the 
relations of the same ridge to the underlying clays of the drift : 
Beye ie Rees ee akan (a eee atere TON IVE i nn ME tb ee AQ 
2. Yellow ciay, with irregular blocks of blue. clay, surrounded with: a yel- 
low oxydized shelk.-..%... ..6--.----2------ BG500 BS650 6009 Go56 abod 20 
3. Sand, with a profusion ef vertical columnar concretions, at the bottom, 
passinc.mto yellow Clay ---. 2 eo. ose oo ce oe ee 10 
4. Blue clay, finely washed, compact, ‘mingled with: sharp, fine gravel, the 
whole eut by vertical, gbligue, . and horizontal seams—the greater 
part vertical—filled vith: yelloww,: silicious clay, cemented intorock.. 20! 
The partings in this blue clay. vary in thickness, frona that of paper to 
one-eighth of an inch, and are so fittely cemented, that where the clay is 
washed away by the rains, they résist.the erosion, and project from the 
bank from three-fourths of an’ dich. te. one and a half inches. The 
cementing material is iron, brought down frona the clays above, and the 
fissures are apparently cleavage seams, produced by compression. 
A few rods to the north of this locality, the well for the Norwalk 
water-works was sunk in the valley, ‘and commences on a level with the 
bottom of the bluff of which: the section: is given above. The materials 
passed through were— = * es pv 
1. Yellow drift clay, passing init Bie a Bees Ab aie a bes ns a eG 
2. Gravel to bottom nsec Sees nee ae monet eee BS HE FV he See Oe ga EW Oey 5 
The fragments of rock. thrown: out. in the excavation, were principally 
granite, green, stone, corniferous, ingestone, and Huron shale. Near the 
bottom of the blue clay, 1 in, this: well, was obtained the remarkable spheri- 
eal concretion originally from. the: ‘Huron. shale, one side of which was 
planed off and striated by glaciak action, which i is figured and described 
by the Chief Geologist, Prof. Newberry, in the first chapter of volume _ 
one. It was obtained seventeen feet below the surface of the valley, and 
one hundred and seven: feet below ‘the base of the sand ridge at Norwalk. 
There is ordinarily: Thor such, accimulation of drift material beneath the 
gand ridge, as 13s indicated. above. West: of Monroeville, the ridge is a 
regular, well marked. beach line;-zising ‘about. ten feet above the plain at. 
the south of it, and fifteen feet ‘above: that at the north. On the south 
side, are the irregular: dunes faentioned above, and on the north, a wide 
stretch of level prairie land. es | 
