44 F\ REPORT OF PROGRESS. E. W. CLAYPOLE. 



below Marysville. Only in two places between these points 

 is this mountain wall interrupted. At the west end the 

 Tuscarora anticline sinks into the ground after passing 

 for some miles parallel with the rising West Tuscarora an- 

 ticline, and between them Liberty valley forms a low level 

 passage from Perry into Juniata county. Again on the 

 south line the Blue mountain runs out of the county into 

 Franklin, and the range of Bower and South Bower passes 

 parallel with it over the county line and ultimately, after 

 passing round the syncline of Clark Knob, both unite in 

 the synclinal point at Jordan Knob near Loudon. 



The Medina sandstone is, on the whole, little eroded in 

 Perry county, and consequently the lower beds show in only 

 a few places. Along the whole range of the Tuscarora an- 

 ticline the white upper Medina occupies the wdiole surface 

 except at Run gap, near Ickesburg, Avhere erosion has ex- 

 posed the lower red bed. In Horse valley, also, where the 

 West Tuscarora anticlinal is cleft, these lower beds, of 

 course, show along the inner slopes of the mountain. At 

 the crossing of Bowers' mountain, south of Blair, on the 

 south slope, is a ravine which shows the red Medina. 

 Also along the southern slope of the Blue mountain is 

 another exposure, for the most part, however, in Cumber- 

 land county. 



These outcrops of the red Medina thin out and disappear 

 before reaching the Susquehanna river. 



The county line in the west runs across the zigzig crest of 

 Bower, Amberson, Rising, and Round Top mountains, and 

 consequently the greater part of the red sandstone lies in 

 the adjoining conn lies. 



The Medina sandstone has afforded no fossils in Perry 

 county, unless the few specimens mentioned above should 

 prove to belong to it. It supplies the chief material for bal- 

 lasting the Pennsylvania railroad for many miles, and is 

 quarried for that purpose at the Juniata gap. 



Wo. Va. Clinton group. 



These rocks have beeii the held for much discussion re- 

 garding their relationship to corresponding beds in other 





