RELATION TO THE ROME OUTLET 363 



of old land surfaces far below the Iroquois beach near Hamilton, and 

 also near Toronto, and likewise of a splitting of the beaches to the north- 

 east of a line running from the Rome outlet to Quays or some point near 

 it ; but it is desirable to present the evidence for this in a more definite 

 way than has been done before. 



If the isobases are represented as straight lines at right angles to the 

 direction of greatest inclination, north 20 degrees east, as shown by my 

 levelings, an isobase passing through the Mohawk outlet runs a little 

 south of Quays gravel pit. The direction formerly given for the greatest 

 uplift is north 27 degrees east, which would send the isobase of the 

 Mohawk outlet 9 miles to the north of Quays, through Silver lake. At 

 this point the beach is already split up into three gravel bars, the highest 

 and lowest 28 feet apart, so that theoretically the line must pass some 

 distance to the southeast, according better with the direction north 20 

 degrees east. 



Taking 3 feet per mile as the amount of spread between Silver lake 

 and Trenton, a distance of 9 miles, the two best water levels being here 

 55 feet apart, the lines will converge at Quays, confirming the evidence 

 obtained in other ways in favor of that point as the node. We may con- 

 clude, then, that the line of no separation of the beaches runs from the 

 outlet near Rome approximately through Quays, which is about 6 miles 

 north of Port Hope. 



If we consider that the amount of divergence between the highest and 

 lowest beach to the northeast of the fulcrum is diminished toward the 

 southwest proportionately to the diminution in the rate of deformation 

 of the latest beach, namely, as 4.17 to 3.4, we shall have a rate of sepa- 

 ration of 2.45 feet per mile ; so that at York, just east of Toronto, the 

 lowest beach, now buried of course beneath the later beach formations 

 of lake Iroquois, should be about 87 feet beneath the highest. Continu- 

 ing the divergence for the 37 miles between York and Hamilton at a 

 rate proportionate to the deformation of the latest beach, which is 2 feet 

 per mile, the highest and lowest beaches would spread 1.44 feet per mile, 

 or about 52 feet. Adding this to the 87 feet of spread between Quays 

 and York, the total divergence should be 139 feet, which would put the 

 first level of lake Iroquois at Hamilton 23 feet below the present level 

 of Ontario at that city. 



It will be understood, of course, that the data derived from the spread- 

 ing of the beaches northeast of the hinge line are not absolutely certain, 

 and also that the supposition of a southwesterly divergence proportional 

 to the rate of deformation of the latest beach is hypothetical, though 

 very probable ; so that the results just given can be looked on only as 

 rough approximations to the truth. They are, however, corroborated to 



XLIX— Bum,. Geol. Soc. Am., Vol. 15, 1903 



