Branner.] d4b [Feb. !9, 



enters the Lackawanna, or it may have heen in the gorge above Archbald. 

 In the latter case the narrowness of the valley between Jermyn and Arch- 

 bald would not admit of a widespread deposit of silt, while the rapid 

 descent of the stream must have combined with this narrowness to 

 cause the washing away of nearly all the sediment that was thrown 

 down between these two places. The rather unusual deposit of large quan- 

 tities of drift on the east side of the river below the Archbald gorge may 

 have been carried down from this narrow valley. This material, composed 

 for the most part of large cobble-stones, and with but little sand and 

 gravel in it, once filled the lower part of the Laurel Run hollow. But this 

 stream has gradually cut it away, until its southern face is now a steep 

 bank from ten to thirty feet high. Below Archbald the valley is nar- 

 row, and the current rapid, as far as Peckville. The next dam appears 

 to have been at Olyphant. Here .the flood plain of the valley narrows 

 very considerably, the rocky hill upon which part of the town is built 

 standing out from the southeast side across the valley, and thus confining 

 the river to a comparatively narrow channel. The damming back of the 

 floods here probably helped to form what are now the meadow lands be- 

 tween Olyphant and Peckville. 



Following down stream, the next case of this kind appears to have been 

 at Scrantou. The city of Scranton is built upon a wide terrace of glacial 

 drift, which, possibly, closes now the original channel of the Lackawanna 

 river at this place. Opposite this terrace the hill upon which Hyde Park 

 is built stands out across the valley, leaving a channel only about three 

 hundred feet wide between the two, and through which the Lackawanna 

 now flows. At or near the close of the glacial epoch, the drift must have 

 dammed up the channel in this narrow neck almost entirely, and the 

 muddy waters that have poured down this valley since the retreat of the 

 ice, spreading out over the flats, have precipitated and deposited upon 

 them the sand, silt, and alluvium of which they are formed. But as the 

 river gradually descended to its present bed, it cut away the western side 

 of the Scranton terrace, until it left its edge the abrupt, high bank along 

 which Mifflin avenue now runs. 



It is particularly true of this, the north eastern, end of the valley, that 

 the drift has been left, for the most part, along the foot of the hills. On 

 the north-western side, along the old plank road, these kames may be 

 seen all the way from Providence to Winton, cut through by the streams 

 flowing down the sides of the mountain. On the opposite side of the val- 

 ley they are not so well exposed, and are, for the most part, overgrown 

 with forest ; but the drift is even deeper and more widespread on this, 

 than on the north-west side. 



The influence of the drift upon the course of the streams in this region 

 has not been so marked as it would have been in a flatter country, the 

 courses of only a few of the smaller ones having been determined by it.* 



♦The change in the bed of the Susquehanna between Plttston and Kingston 

 is referred to elsewhere. 



