22 Cincinnati Society of Natural History. 



The elevation of the land, in this vicinity at least, was very 

 gradual, so much so that no distortions or flexures of any conse- 

 quence were produced in the strata, and they rose above the sur- 

 face in almost perfect horizontality, with the exception of a slight 

 dip to east, west and north. In our vicinity there appears to be 

 evidence of depression as well as elevation. At intervals both 

 forces have acted. Well defined sea beaches are found at at least 

 two horizons in this locality. One of these is at about low water 

 in the Ohio river, and the other one at between 300 and 400 feet 

 higher. The lower one of these beaches is characterized by a cer- 

 tain peculiarly waved structure of the rocks, and also by various 

 mud cracks, tracks and markings which could only have been 

 made and preserved near the margin of an ocean, or on absolutely 

 exposed surfaces of land. Prof. Orton describes the appearance of 

 the rock presented at low water mark on the Kentucky side of the 

 Ohio river at Ludlow excellently, and I can testify that his de- 

 scription is accurate, as I have seen it many times. He says :* 

 " The rocks exhibiting this (waved) structure are the most compact 

 beds of the fossiliferous limestone. The bottom of the waved 

 layer is generally even, and beneath it is always an even bed ot 

 shale. Its upper surface is diversified, as its name suggests, with 

 ridges and furrows. The interval between the ridges varies, but 

 in many instances it is about four feet. The greatest thickness of 

 the ridge is six or seven inches, while the stone is reduced to one 

 or two inches, at the bottom of the furrow, and sometimes it en- 

 tirely disappears. The waved layers are overlain by shale in every 

 instance. They are often continuous for a considerable extent, 

 and in some cases the axes of the ridges and furrows have a uni- 

 form direction. This direction is south of east in the vicinity of 

 Cincinnati, but in traversing the series, these axes are found to 

 bear in various directions." 



The shore line as here considered must, of course, have been 

 formed at an earlier period than that at which the strata above 

 were laid down. And during this deposition the former shore 

 line must have been underwater, and then it was that three or 

 four hundred feet of rock were formed. Part of this time must 

 have been a i)eri()d of subsidence, at the end of which there came 

 an upheaval, and the second shore line was formed. This beach 

 lies between three hundred and fifty and four hundred feet above 



*Ohio Geol., I., p. 377. 



