Correspondence — Prof. J. P. Leslei/. 335 



the striae and drift deposits are described as covering the high lands 

 of the State. The line of moraine mounds and hollows, with large 

 boulders, crosses Schooley's Mountain at an elevation of between 

 1200 and 1300 feet. Back from this, to the N. and N.E., the 

 mountain ranges are drift-covered as well as the valleys, but the 

 mountain crests are nearly destitute of drift, although boulders are 

 perched upon them. A large glacial map of New Jersey accompanies 

 this report. The report of 1879 gives a still larger coloured geo- 

 logical map of the State ; and this also shows the drift-covered area. 

 The report of 1880 describes the terminal moraine in great detail, 

 with a table of elevations (highest in Waterloo township, 1250' A.T.) ; 

 moraines of recession ; modified drift ; transported drift ; preglacial 

 drift; drift dams and ponds, etc. The report of 1881 gives the 

 heights of Hamburgh mountain as 1488'; Scotts mountain 1277'; the 

 Schooley mountain range as varying from 900' to 1500'; the Kitta- 

 tinny (Schawangunk) mountain as 1474' at the Delaware water-gap, 

 and 1800' at the New York State line, the highest ground in the State. 

 The reports of progress of the Second Geological Survey of Penn- 

 sylvania describe much higher drift-covered areas. I am putting 

 through the press Eeport G 6 (by Prof. I. C White) on Pike and 

 Monroe counties, which border on the north line of New Jersey. 

 Through these counties ranges the high plateau of the Catskill 

 mountains (Devonian), from N.E. to S.W.. cut by the long canons of 

 the Delaware and Lehigh rivers descending from the north. In 

 New York State this plateau averages 3000' above tide, with peaks 

 (measured by Guyot) Overlook 3600', Monk 3880', Blackhead 

 3965', and others up to 4052', 4179'. But in Pennsylvania the 

 average height of the plateau is under 2000'. The Delaware and 

 Lackawanna railway crosses it with a summit grade of 1681'. Near 

 this lies Elich's pond in a kettle of glacial drift at 1754'. The front 

 edge of the escarpment (a horizontal conglomerate 100 feet thick) 

 ranges at about 2000' A.T. From this front edge the plateau 

 slightly declines north-eastward, with outlying fragments, such as 

 North and South Knobs (2010' A.T.). But northwards it maintains 

 its elevation ; the railway summit grade being 1955' next south of 

 the Tobyhanna creek, and 1970' next north of it. This Tobyhanna 

 creek flows under the railway bridge at 1932' A.T. through a very 

 shallow valley of drift. 



Pocono Knob projects eastward from an angle of the escarpment 

 (where it turns north), and is about 2000' A.T. The notch behind 

 it which isolates its summit from the rest of the plateau is 1681' A.T. 

 Another Knob on the brow of the escarpment reaches 2225' A.T. 

 The terminal moraine creeps up the escarpment, encircles Pocono 

 Knob at two-thirds its height (from base to top, say 1000'), and 

 reaches the plateau level from behind. From this point it stretches 

 off N.W. across the plateau at a height of 2000' A.T. in the form of 

 a mound- wall about 100' high. Long Pond has been created by it, 

 obstructing a preglacial valley with its trash. 



The entire area of the plateau behind the terminal moraine, i.e. the 

 whole of Monroe, Pike, Wayne, and Susquehanna counties lying to 



