152 J. L. Rich— Physiography and Glacial Geology 



one or two to six or eight feet thick. Both till and lake clay 

 are composed of red local materials. Foreign rocks are found 

 only rarely. 



For a couple of miles below this loop the valley is nearly 

 free from drift. On the hill slope, however, near where the 

 stream swings against the west side of its valley, opposite Mt. 

 Royal, is a fairly distinct morainic mass, convex down stream, 

 and composed of local materials. Rather careful examination 

 here failed to show more than a very few foreign stones. A 

 hundred yards farther down stream is the great morainic mass, 

 200 feet thick above river level, which chokes the valley for 

 several miles to the north. Here the drift is entirely distinct 

 from that only a few hundred feet up stream, and is typical 

 northern till. Foreign stones — limestones, gneisses, schists, etc., 

 constitute a large percentage. 



A rough section of this thick till mass as exposed in the 

 stream-cut bluff opposite Manorkill Falls is reproduced below. 

 The base of the section is about 15 feet above mean river 

 level. All figures are approximate only. 



Top 



Yellowish blue, coarse bowldery till, less compact than 

 that at base of bluff. Large percentage of north- 

 ern material clear to top _ 50 feet 



Yellow sand 6 " 



Partly covered — probably bl ue till 75 " 



Homogeneous pebbly blue till (crumpled) 5 to 10 " 



Homogeneous pebbly blue till 15 " 



At base, blue northern till, irregularly mixed with 

 clay and very fine sand. Percentage of foreign 

 pebbles very large — probably 50 per cent 20 " 



Another rough section of the same mass was taken along the 

 gully (of the main tributary) just south of Gilboa village. 



At top, yellowish blue, northern till, relatively little 

 local material, large bowlders, and only a moder- 

 ate proportion of clay. Bowlders mostly of north- 

 ern origin. Not particularly compact 60-70 feet 



Unstratified, dark, slate-blue clay with many small 

 pebbles, with but few large bowlders — the clay 

 very free from grit. 40-50 " 



Drab to slate-blue stratified clays— layers extremely 



thin ; no pebbles, and no grit variable 



Below this comes more of the blue bowlder clay, 

 then occasional small outcrops of the stratified 

 clay — some apparently included in the till. Still 

 lower, just above first road crossing, is an expo- 

 sure of crumpled stratified clay carrying occa- 

 sional thin layers of red sand. 



