2. CARROLL TOWNSHIP. F 2 . 163 



the softer shales of the upper Hamilton and Chemung 

 groups. 



The ridge road to Carlisle from New Bloomfield passes 

 over the Rock hill at a place about two miles from the Rock 

 where the crest is slightly lower than usual, but the de- 

 pression in no wise deserves the name of a gap. 



The road from the county-seat to Duncannon also passes 

 through the Hamilton sandstone range at Rattlesnake hill, 

 but here also the depression is slight. No water comes 

 fJtrough it from the head of upper Sandy Hollow. The gap 

 is only in course of formation and will require many thou- 

 sands of years for its completion at the present rate of pro- 

 gress, the little stream which heads near its north side 

 being capable of doing only a small amount of erosion on 

 the sandstone. 



The second outcrop of the Hamilton sandstone is on the 

 south of the township where under the name of Little 

 mountain it runs in an east and west direction parallel with 

 the Blue mountains. The dip of the beds is here much 

 steeper than farther north and the passes are consequently 

 shorter. 



The Hamilton fossil ore. 



The bed or beds of this ore pass through the township 

 along the southeastern slope of the Rock hill. Traces of 

 the presence of ore may be seen in many places but none 

 has yet been taken out. From fossil evidence it is probable 

 that the three beds described in the account of Wheatfield 

 township also occur here. Nor is there any reason to doubt 

 their presence in Little mountain. 



The ore bed has been exposed on the southeast side of 

 the Rock hill on the land of Mr. Hicks but no attempt has 

 been made to work it. Indeed it would probably be un- 

 profitable. The ore is very fossiliferous, holding the same 

 species as near Marysville. 



The Hamilton Upper shale. 



Good exposures of this bed occur along the south side of 

 rli" Rock hill between the Hamilton sandstone and the road. 



