142 



that the moix^ imiioitaiit sandstone, gritstone and conglomerate formations 

 may be seen. Their ontcroppings are especially lioticeable along the slope 

 south of Crooked creek, and between the large fill of the Pennsylvania rail- 

 road and the bridge over Crooked creek on the Hanover road. 



So far as determined from sections seen in a few short valleys, on the 

 creek banks, and in a large gravel pit, the consolidated sands and gravel 

 are more abundant on the side of the bar farthest from the river, and on 

 the slope near the creek. Hera the conglomerates and sandstones are in 

 several irregularly placed layers which vary in thickness from a few inches 

 up to six or more feet. The formations are not of uniform thickness, and 

 grow thinner the farther they are from the creek and the exposed slope. 

 The accompanying ideal cross section of the portion of the bar from 

 Crooked creek on the north to the Ohio river on the south in the locality 

 above mentioned shows the relative position and general character of the 

 formations. 



The cementing material, so far as tested, was found to be calcareous. 

 Much of the stone is quite compact and firm, but a part of it is more or 

 less friable. In general the upper portion of any layer is the more indu- 

 rated. In a few limited areas the upper surface of the conglomerate ap- 

 pears to be cemented by material of stalagmitic character. By far the 

 greater part of the formations, however, gives no evidence of the existence 

 of cementing material of tlint nature or origin. 



The formation is peculiar from the fact that the cementation and con- 

 solidation took place above the water and in the absence of any consider- 

 able pressure. In the opinion df the writer the cementation of the sands 

 and gravels was the result of capillary action. The waters of Crooked 

 creek, v.hich flow throughout their course over limestone and calcareous 

 shales become at times strongly impregnated with calcium carbonate. This 

 was preeminently the case when the stream was low at the time of a 

 drouth. On the arrival of the waters at the place of the present conglom- 

 erate formations, the slope of the stream and the character of the bed were 

 such that the movemenr of the water was very slow. Hence much of the 

 water with its content of calcareous material passed into the sandy and 

 gravelly banks, and tlien was drawn up by means of capillary action 

 through the firmer ciose-textured beds. On approaching the surface of the 

 beds the water evaporated a.i)d left a residue of calcium carbonate. This 



