PLEISTOCENE GEOLOGY OF MOOERS QUADRANGLE 45 



an elevation of about 540 feet (aneroid). This is the highest of 

 a group of strongly developed benches which can be traced along 

 the northern base of Covey hill for several miles. Their surfaces 

 are frequently strewn with coarse angular blocks of sandstone, 

 though half a mile east of Stockwell postoffice a bar at 520 feet 

 shows coarse, waterworn material. Gravelly beaches begin in this 

 direction at 450 feet. Above this line the materials are coarse 

 stones. The road follows the upper ridges at least as far as 

 Rockburn. 



At Franklin Center, as indicated on the adjoined sketch map, 

 which is designed only to show the general orientation of the 

 roads, the 570 foot bench with a cliff cut in the till is distinctly 

 shown. North of the main road is a succession of beaches and 

 ridges down to at least 396 feet. All readings are aneroid com- 

 pared with the top of Covey hill. First and just north of the 

 crossroads is the crest of a bar at 480 feet, with waterworn 

 pebbles on the bas^e of the beach slope at 450 feet. At a slightly 

 lower level and farther north is a weak beach ridge. North of 

 the crossroads there is a beach ridge 430 feet at top, with water- 

 worn gravel down its northern slope to 400 feet. This beach is 

 confronted by a flat whose surface is at 396 feet. The upper stony 

 ridges become stronger and more distinct toward Rockburn, 

 beyond which point within Canada 1 have made no attempt to 

 trace them. 



Dr Gilbert, in his manuscript notes, placed the upper marine 

 limit at Covey hill at 450 feet. With this decision I agree. 



Taking the 450 foot line as the upper marine limit at Covey 

 hill, the rude terraces above that level would appear to be of 

 .the nature of stream cuts partly made in the till of the hill- 

 side at the time the ice front still pressed against the base of 

 the hill. As soon as the ice began to melt back from the hill 

 the water which had been heretofore forced across " the Gulf" 

 spillway would find a lower pathway about the northern base 

 of the hill and thence into the Champlain valley. The rude 

 beach deposits along the international boundary on the Mooers 

 quadrangle from 540 feet downward to and even below the 500 

 foot contour line are the local equivalent of this state of affairs, 

 but there probably was open water in that field. 



