1879.1 ^ L '° [Stevenson. 



The black clay of the first section, commonly known as the "swamp 

 clay," was reached in a boring here at 25 feet from the surface. In it, 

 amid the numerous fragments of half-rotted wood, the cupule of an acorn 

 was found along with what seemed to be berries of the black haw. The 

 latter were thoroughly carbonized and crumbled rapidly on drying ; but 

 the acorn cup was still tough, and it was kept for some time as a curiosity. 

 The wood in this clay is tough enough to snap in breaking and it has the 

 peculiar tint characterizing the half-rotted wood so frequently seen in 

 peat bogs. 



A point of the third bench projects towards George's creek at a little 

 north from the road. Unio shells, much decayed, are common here and 

 are barely covered by the soil. 



A rise in the road at half a mile nearer to New Geneva brings it again 

 to the level of the fifth bench. There a small deposit of glass sand was 

 found, but it was soon worked out. It rested on an irregular deposit of 

 clay ami sand. 



This fifth bench is continuous along the river hills from the State line to 

 the mouth of George's creek, except where cut away by streams, but some- 

 times it is so defaced by erosion as to be recognized only with difficulty. 

 It is handsomely preserved at Greensboro', on the west side of the river 

 opposite New Geneva, where it shows vast numbers of rolled stones. 

 Mingled clay and sand occur above it to 300 feet above water level. 



Between George's Creek and Bedstone Creek. Below Greensboro' on the 

 river hill, benches occur at 20, 180, 265 and 310 feet above low water. At 

 the mouth of Whitely creek, in Greene county, the third bench of the 

 Stewartstown series, at 180 feet, is very distinct up the creek to the village 

 of Mapletown, and polished fragments are numerous all the way. At the 

 mouth of Muddy creek, in the same county, the fifth bench, covered with 

 rolled and polished stones, is handsomely shown, and along the creek it is 

 quite perfect as far as Carmichaels, where the detrital coating is as thick 

 as it is along the river. 



On Pumpkin run, in the same county, this bench is shown with the 

 same features. The measurement given in the Greene and Washington 

 report* is erroneous and the bench is con founded there with one which was 

 not seen in the Stewartstown series, 'out which seems to be intermediate 

 between the fifth and the sixth, and to be persistent along several of the 

 streams in Greene county at 30 feet above the fifth bench. At the mouth 

 of Ten-mile creek the first, third and fifth of the Stewartstown series are 

 shown, together with the supplemental one just mentioned ; while at Fred- 

 erick, in Washington county, or rather, at two miles back from the river, 

 and near Frederick, is a still higher one, which is clearly the same with the 

 eighth of the Stewartstown series, though the erroneous measurement 

 given in the Greene and Washington county report would make it inter- 

 mediate between that and the seventh, 



* During pari of the season of 1875 I used a barometer which proved to be quite 

 bad. In this way came the erroneous measurements referred to. 



PROC. AMER. PIIIT.OS. SOC. XVIII. 104. 2l. printed SEPT. 20, 1879. 



