FOURTH REPORT OF THE DIRECTOR I907 21 



at points north of Burke and Malone. Topographic sheets of the 

 region are necessary for the mapping. 



The sea level waters in the Ontario basin, called Gilbert gulf 

 have left definite shore features which had been mapped previous 

 to this season as far north as the mouth of Stony creek, 3 miles 

 southwest of Henderson. During the summer the mapping has 

 been carried northeastward to Stone ]\Iills, on the Theresa quad- 

 rangle. 



The highest Gilbert gulf bars lie at about 262 feet altitude near 

 Texas, northeast of Oswego, where the water plane passes beneath 

 the level of Ontario. The plane rises to the north so that the 

 highest bar is 325 feet at Henderson Harbor ; 375 feet at Dexter ; 

 380 to 390 feet at Stone Mills and Depauville; and about 400 feet 

 at Clayton. Along the nearly north and south line of 46 miles 

 between Texas and the Hogback hill, 4 miles southwest of Clayton 

 the average rise is about 3 feet per mile. With the assistance of 

 Mr F. A. Hinds of Watertown the altitude of the highest of the 

 strong Iroquois bars on the Farr place, 3 miles east of Watertown, 

 was determined by precise leveling as 733 feet, a reduction of 7 

 feet from the previous aneroid figures. Using this corrected alti- 

 tude we find that the deformation of the Iroquois shore in the 

 stretch between Richland and Farr's is 733-566-^30 miles = 5.6 

 feet per mile. It appears therefore, that the average uplift on the 

 Iroquois shore in this region is nearly twice that of the marine 

 beaches, which fact has an important bearing on the time relations 

 of the two water bodies. 



Before the details of the closing stages of the Preontarian waters 

 can be advantageously studied and the dramatic history fully written, 

 the topographic sheets of the areas northwest and north of the 

 Adirondacks must be published. The sheets more specially needed 

 for this study are the four along the State boundary lying between 

 the published Mooers and Massena sheets; also the sheet east of the 

 Carthage sheet. 



Aside from these items of Pleistocene history in the regions 

 referred to, a review has been made of contemporary features of the 

 Upper Genesee valley with special reference to the relations of the 

 preglacial drainage and glacial lakes of the river to the production 

 of the gorge and cataracts at Portage. 



The region under study by Professor Brigham includes the 

 Broadalbin, Gloversville, Amsterdam and Fonda quadrangles, an 

 area of about 900 square miles, reaching from the southern Adiron- 



