294 GEOLOGY OF OHIO. 



only remains to inquire what is the origin of this acid, and how it can 

 be removed from the soil, or have its injurious properties neutralized. 

 The underlying rock is the Haron shale, which is filled with nodules and 

 concretions of the bi-sulphide of iron. Wherever this is exposed to the 

 joint action of air and water, it is decomposed, the sulphur set free, and, 

 uniting with the oxygen of the air, produces sulphuric acid. These 

 changes are facilitated by cultivation, and by more perfect drainage of 

 the soil, so that the steps taken to improve the soil only aggravated the 

 evil. If this is the cause of the difficulty, the remedy is easily found — 

 a generous dressing of ashes, or of quicklime, will be sufficient. The 

 lime, uniting with the acid, will form sulphate of lime, or " plaster," of 

 itself a good fertilizer. The alkali must be well mixed with the soil, 

 and the application may have to be repeated, until all the pyrites within 

 reach of atmospheric influsnces, has decomposed, and yielded up its sul- 

 phur. In a similar case, in Trumbull county, a single application, made 

 some ten or twelve years ago, was sufficient to neutralize the acid, and 

 no repetition of the remedy has been required. The amount of lime 

 needed can only be learned by experiment. As the railroad, from San- 

 dasky, where there is an abundance of limestone, passes directly through 

 these " bad lands," they can probably be rendered productive at compar- 

 atively little expense. 



Eist of Norwalk the sand ridge has a gently waving contour on the 

 north, and is bounded by a broad water plain, except as modified by 

 recent erosion. On the south it is very irregular in its outline, the bil- 

 lowy round dunes being of varying heighfr-and form, and often extend- 

 ing a long distance from the ridge. The materials of the ridge are, at 

 the top, finely washed sand, resting upon gravel, with a profusion of 

 granite bowlders, and below this, bowlder-clay or bed-rock. This is the 

 only well-marked and continuous sand ridge in the county, a winding 

 highway, thrown up by the action of the waves, resting in places directly 

 upon the bed-rock, in others upon the coarser materials of the Drift clays, 

 sometimes burying beneath it the debris of the old shore swamps, and at 

 others extending over chasms one hundred or more feet in depth, fl'lled to- 

 the general level with drifted material. The deep ravines in the bed-rock, 

 now filled with Drift, and the general contour of the rock surface here and 

 in other parts of northern Ohio, indicate a peculiar topography before the 

 period of the Drift, )viz., a broad expanse of rock surface, disintegrated in 

 places sufficiently to form a soil fitted for the support of forest trees, with 

 a net-work of deep channels, which are now filled with Drift, but which 

 largely determined the location of the present lake chains and river courses. 



Granite bowlders of various sizes may be occasionally seen projecting 



