354 A. P. COLEMAN — IROQUOIS BEACH IN ONTARIO 



ing southward from the morainic ridge called the Oak hills, and here for 

 half a mile the waves of lake Ontario have eaten back the Scarboro 

 cliff so far as to destroy the old beach. East of Scarboro heights the 

 shore bends to the northeast till it is nearly 8 miles from Ontario near* 

 Whitby, but one of the boldest promontories on the whole shore projects 

 southward again at Newtonville, beyond which there is another deep 

 bay reaching 7 miles from lake Ontario with a drumlin island offshore 

 not far from Port Hope. By the hand level the bar at Quays gravel pit, 

 north of Port Hope, is found to be 311 feet above Ontario. 



From this point the beach is carved in the bold morainic ridge crossing 

 central Ontario, and as far as Colborne presents the usual characters in 

 such a position — bold cliffs of boulder clay 50 or 100 feet high with small 

 gravel bars across the depressions in the hills. The whole beach from 

 Niagara river to Hamilton and Colborne is conspicuously a unit, with 

 no distinct splitting up into higher and lower bars. We may suppose 

 that the old bars rose a few feet above water, as we find to be the case 

 on' the shore of lake Ontario, but, as on the modern lake, the water level 

 probably averaged not more than 5 feet below the top of the bars. To 

 the east of Colborne, however, the beach loses its unity and different 

 water levels show themselves. 



Colborne to Trenton 



At Silver lake, 3 miles northeast of Colborne, on a promontory facing 

 southeast, there are massive bars at three levels, the highest 28 feet above 

 the lowest, and as along the previous coastline the difference between 

 neighboring bars has never been found to exceed 10 feet, we must con- 

 clude that there was an actual shifting of water levels to cause so great 

 a divergence here. Silver lake is really a small bay cut off from lake 

 Iroquois, and now draining north through a valley crossing the moraine, 

 and turning east into Trent river, instead of emptying, as one would ex- 

 pect, into lake Ontario two miles and a half away and 360 feet lower 

 down. Evidently a narrow strait cut off a large group of hills between 

 Silver lake and Trenton in Iroquois times, and heavy wave action from 

 the broad lake to the south piled up gravel enough to cut off communi- 

 cation in that direction, leaving the modern stream to find its way 

 northward. 



North of Brighton gravel bars occur at different levels once more, and 

 this is still more pronounced 3 miles northwest of Trenton, where the 

 hills end sharply in a bold promontory facing eastward, while the 

 boulder strewn terrace beneath slopes gently away on the north, east, 

 and south. The level of the main beach near Trenton was determined 

 by Doctor Spencer a number of years ago, but in different publications 



