Hall ] 6-0 [Sept. 17, 



NOTES ON GLACIAL ACTION VISIBLE ALONG THE KITTA- 

 TINNY OR BLUE MOUNTAIN, CARBON, NORTHAMPTON, 

 AND MONROE COUNTIES, PENNSYLVANIA. 



By Chaiiles E. Hall. 



{Bead before the American PMlosopMcal Society, September 17, 1875.) 



My attention was first called to the fact of glaciers having existed along 

 tlie Blue Mountain and south of it, from the vast deposits of boulders and 

 pebbles south of the Lehigh Gap, and along the course of the Lehigh 

 River. My observations have been limited, not having had time to de- 

 vote to the subject. 



South of the Lehigh Gap, about one-half mile below the chain bridge, 

 on the east side of the river is a railroad cut through the slates of the 

 Hudson River group, overlaid by a large bed of sands, gravel and 

 boulders, having all the characteristics of a glacial deposit. 



The slate has a dip to the southeastward,* the upper edges of it are 

 broken and crushed over to the southward, thus showing a force and 

 weight moving in a sou.therly direction and obliging the slates to con- 

 form to it. 



A similar exposure was observed three-fourths of a mile below Bow- 

 man's (second station above Lehigh Gap). Here in a railroad cut 

 through the shale of VI, on the east side of the river, the rock is ex- 

 posed for more than a hundred feet. 



The rock dips S.30OE., the line of the exposure isS.40OE,, and parallel 

 to the exposure, or diagonally aci-oss the strike, are the edges of the shale 

 overturned and broken, in some places to a depth of five or six feet. 

 Here, too, the broken edges all incline to the southeastward, indicating 

 the direction of the moving mass to be towards the Gap. The shale is 

 very much crushed near the surface ; above it is a heavy bed of fine sand, 

 angular fragments of rock, and large boulders, most of them are from the 

 Oriskany, some from the Chemung, but none from the Medina of the 

 Blue Mountain. 



Two hundred yards back of the Hotel at Bowman's, on the road to 

 Fireline, the slates of the Hamilton present a similar appearance. The 

 upper edges overturned and broken, and here show a movement to the 

 southeastward. 



We may conclude from these facts that the bed of the present river 

 marks, to a great extent, the course of the glaciers. 



To the east and west of the Gap, north of the mountain is a broad flat 

 valley extending from the Oriskany Ridge to the base of the mountain. 

 This valley is intersected by a barrier of debris extending from the 

 Oriskany Ridge to a rounded hill of Clinton Shale and sandstone, a few 

 hundred yards north of the Gap. 



My attention was first called to this fact by Mr. H. Martyn Chance, 

 who was then making a survey of the Gap. 



The only explanation I can give of this, is, that it is a moraine formed 



