

300 F 3 . REPORT OF PROGRESS. E. W. CLAYPOLE. 



mile south of Losh's Run Station on the Pennsylvania rail- 

 way. 



Its next appearance, so far as I am aware, is on the road 

 leading west from the Aqueduct. 



There is no trouble in following it from this point by an 

 almost uninterrupted series of exposures to Duncannon. 

 Its course is marked by the red color of the soil, for a mile 

 due south, across iields, to the road running west from the 

 railway station at Juniata bridge. 



Here a pit was sunk some years ago in quest of ore on the 

 western edge of the dyke, to a depth of about 25 feet. A 

 drift was then run for 6 feet into it in the attempt to pene- 

 trate it. This made its thickness upwards of twelve feet. 

 The same discolored sandy shales were thrown out here as 

 in the Cove. 



At this point the direction of the dyke suddenly changes ; 

 but a thin vein of trap appears to continue nearly on its 

 former course, as indicated by an occasional trap pebble in 

 the low ground. Such pebbles have been found in the run 

 close by the place where the change occurs, near the grist 

 mill west of Duncannon, and again at a short distance behind 

 the nail factor\ r . These are sufficient to indicate a faint con- 

 tinuation of the dyke in its former direction as far as to the 

 north foot of Peters' mountain. An examination of the 

 ma}) will show that it is on the line of dyke No. 3 in the 

 Cove, before described. 



But the main mass of the dyke suddenly bears away at 

 S. 30° E. down a slope, across a field, passing under a 

 house (as shown when the cellar was dug) and so reaching 

 the river 



It has not been seen in the bed of the river ; but on the 

 opposite or eastern river bank, opposite the mouth of Sher- 

 man's creek, and exactly on the right course, what is prob- 

 ably the same dyke is displayed in a cutting of the North 

 Centra] railway. This exposure gives an opportunity of 

 measuring the thickness of the dyke, which is about 50 

 feet. It dors not appear to rise to the surface; and the 

 locks on both sides are altered as in the case of the Great 

 Horseshoe dyke in the Cove. 



I 



