1890.] NATURAL SCIENCKS OF riIILADP:LPIIIA. Ill 



200 feet liigli divided by a branch of Dismal Run into a smaller hill 

 on the northeast known as Roundtop and a much longer one to- 

 ward the southwest called Poplar Hill. Dismal Run seems to be 

 the boundary between the Laurentian on the northwest and the ser- 

 pentine on the southeast, flowing in a remarkably straight course 

 about N. 60° E. The road mentioned as crossing the Lenni- 

 Lima road at the Barren Hill schoolhouse shows the serpentine in 

 quantity with its characteristic vegetation immediately southeast of 

 Dismal Run, but as soon as the higher land is reached the serpen- 

 tine disappears, and honeycomb quartz is found in the soil in greater 

 or less quantity, but no rocks in place. 



To avoid confusion I should state that there is another " Barren 

 Hill Schoolhouse " in Marple about a mile and a half north of 

 Palmer's Mills. The authorities, with characteristic economy, seem 

 to have selected the serpentine outcrops in this vicinity as sites for 

 Public Schools, perhaps upon the theory that knowledge would grow 

 where nothing else would, but a worse education for the young can 

 hardly be found than the surroundings of the three contiguous 

 schools of INIarple, Blue Hill, and Middletown, They are a disgrace 

 to our civilization. 



Eastward along this road, about a quarter of a mile from the 

 schoolhouse, on an aflluent of Ridley creek, occur great quantities of 

 the honeycomb quartz, completely covering the ground, but even 

 here the vegetation is not characteristic of the serpentine. About 

 a quarter of a mile further east a steep bluff on the north of the 

 road discloses the schists and in them a large mass of kaolinized 

 feldspar, whether a bed or dyke is not clear. A short distance 

 beyond, the road runs into the road from Lima to the Rose Tree Inn, 

 and on this also the schists are seen. This brings us about a half 

 mile northwest of our point of departure at Ridley creek and the 

 railroad. 



Examining now the more central part of the area we find on the 

 State road, east of the road from Lima to Glen Riddle, loose honey- 

 comb quartz, but at the foot of the hill, where Chrome Run crosses, 

 two quarries in granulite. This rock lies in beds from a few inches 

 to a foot in thickness, rarely more, and it is excessively jointed. 



East of this is more honey-comb quartz and a little serpentine. 

 On the same road east of the Black Horse tavern there is more 

 quartz. About a quarter of a mile east of the tavern a small stream 

 flows northeastwardly into Ridley creek. Its valley and the next 



