EARLf DEVONIC HISTORY OF NEW YORK AND EASTERN NORTH AMERICA 53 



A simple combination of two causes has contributed to the destruction 



of this mass, the sea and the frost. The destruction has gone on by 



leaps and bounds in the falling of arches carrying down thousands of 



tons of rock at a time, though the times were distant intervals. But the 



steady work of the less destructive agents never ceases. From Nicholas 



Denys's statement in 1672, that on his first trip to Perce there was only 



one arch in the rock, as Champlain saw it in 1603 but when he returned 



some years later he observed two others, and that subsequently in his day 



one of the latter broke down, it is evident that the progress of destruction 



then went on at a rapid pace compared 



with its advance during the last century. 1 



But these arches have all been at the thin ' 



outer edge of the cliff which easily became 



honeycombed. This thinner part of the 



rock is now nearly gone and the waters 



have a more serious problem before them. ! 



A thinuf of singular beaut\- indeed the 



long rock with its three or four arches, in 



the da)"s of the i6oo's, must have been, i 



Today its proportions are more stable, 



for the single perforation lies under one "" ""^'' " '^ 



of the highest parts. Though its rearward obelisk is giving way and is 



perforated at its base the splendid mass itself is not perceptibly thinning 



to destruction. 



Let us look a little to its future. 



We have given above the dimensions of the rock. That part of it 

 exposed to the action of sea and frost has a volume of about 6,000,000 

 tons. From the broken vertical strata the fragments fall easily under the 

 winter's storms but they are wedged in tight and in all my wanderings at 

 the foot of the cliff I have observed only an occasional rain of small frag- 

 ments. However the base of the cliff is covered with large blocks and the 

 shores of Mt Joli made up of its fragments. There are projecting angles 

 of the rock where blocks lie in piles of 10-20 pieces weighing from 5-10 

 tons each but these are the accumulations of no one seems to know how 

 many years. The amount of annual fall of rock would be little more than 

 a probable guess and any average would be broken by the occasional fall 

 of an arch. This latter factor is however now practically eliminated. 

 After careful questioning of the residents and observation of all the 

 conditions I should regard 300 tons per annum a fair average of fall, 500 

 tons large and 1000 tons highly improbable. With the first approximation 

 it will take sea and weather upward of 20,000 years to accomplish the 

 ruin of the little island, with the second 12,000 and with the third 6000 



