72 



... W. SPENCEB — ANCIEN1 SHORE PHENOMENA. 



these deposits, Leaving high clay binds, in other localities the coast r 

 gently from the water-line In front of these shores, whether high or low, 

 beaches often occur. The typical beach forma a ridge of stratified sand and 

 gravel, rising from three to five feet, or even inure, above the Burface of the 

 water. The ridge may vary from a lew yards to as many scores, or even 

 hundreds. In the mure perfect form, there is :i slight depression behind the 

 ridge which is sometimes occupied as a bay. lagoon, or swamp < fig. 1). 



FIGURE I.— Section showing the Floor of a Cut Terrace on which rests a Bench. 

 '. and c = Beaches broken into ridgelets. d = A frontal sand bar. W= Old water-level. 



Whilst the beach may form a frontal barrier, in shallow waterj distant from 

 the Bhore, it may rest directly against the coast, funning a terrace (a, fig. 2 , 

 behind which there is no depression. In this case the surface of the terrace 

 is apt to he defaced by landslides or washes; but the beach, whether in the 



Figure •-'.—> Floor of •< '/'■ 



f construction resting on cut terrace. P Frontal pavement of boulders. W Old 

 i r-level. 



form of a terra< r off-shore barrier, Is very often wanting when the currents 



are cutting into and washing away the coast i fig. 3). Under such a condi- 

 tion, if a beach he funned, ii is narrow ami temporary, a- it is liable to be 

 washed away or covered by landslides. The eastern ami southeastern coast 

 of Lake Huron commonly illustrate the absence of true beach structure. 

 Another excellent example may be seen at Scarboro heights, a few miles east 

 of Toronto, on Lake Ontario, where the clay banks rise to the heighl <>l' 

 more than 200 feel and extend fur a distance of uine miles. Here the cliffs 

 ;ii'- being eroded. The waves are nut forming a permanent beach, but the 

 currents are drifting the materials Beveral mil.- to the west to build up the 

 barrier-beach in front of Toronto harbor. 



