GIBE ON CANADIAN CATEENS. 



165 



perforated rocks. Alilion-gli frequently seen by mai-iners and others, 

 the only account published of them is in a paper by Captain (now 

 Rear-Admhal) Bayfield, in the fifth volnme of the Transactions of 

 the Geological Society, second series, wherein a plate is given of a 

 number of natural columns on the east coast of ISTiapisca Island. 



These curious columns are met with in most of the islands far 

 above the reach of the highest tides, running along the ancient 

 raised beaches. A pictui'esque gToup is found on the west side of 

 Large Island, a mile to the northward of its south-west point. Here 

 hundreds of flower-pot and arched rocks stand up out of the rising 

 tide to heights varying from ten to fifteen feet on the flat limestone, 

 -^^th breadths from a few feet to thii'ty or forty, widening at the top. 

 Many again are above high water mark; and many stragghng 

 flower-pots are seen high up in the island, and with the succession 

 of raised terraces strikingly illustrate the relative levels of the sea 

 and land, when from fifty to sixty feet different to what they are at 

 present.* A remarkable flower-pot rock is to be seen on the south- 

 west point of the Outer Bhch Island. 



According to Admhal Bayfield, most of them vary in height from 

 fifteen to thuiy feet ; some even exceed forty feet above the plateau 

 of rock on which they stand. They are frequently aiTanged in lines 

 upon teiTaces of hmestone, precisely similar to those which are at 

 present forming out of cliff's that are washed by the waves. Tliis is 

 especially the case at the eastern end of Kiapisca Island, where the 

 largest and most remarkable group of these rocks is to be seen. 



It seems to me that there cannot be any doubt as to the manner in 

 which these curious natural objects have been formed, namely, from 

 the effect of the waves at different levels, as we see the same process 

 going on at the present day. Great or small holes are broken by 

 the sea into the limestone clifis ; these become larger and larger, 

 spreading in various directions, when the roof of the caverns gives 

 way, and leaves one or several pillars with a small base to support a 

 partially arched top. The angTilar m-egiilarities of the upper part 

 of the pillar become worn away by the action of the sea and of the 

 elements, as the land slowly rises, and we have what certainly 

 resemble floT\ er-pots, towers, and incomplete arches situated high up 

 above the influence of the tides, and formed as it were of horizontal 

 layers of limestone piled one above the other. 



A section of Large Island was found by Mr. Richardson of the 

 Canadian Geological Survey, to be composed of limestones of the 

 Chazy, Bird's-eye, and Black-river formations, exceedingly favourable 

 to the wear of the sea into arches and perforations. Most of the 

 other islands are formed in the same strata, the most northerly, 

 however— Harbour Island, consisting of the calciferous sand rock, 

 which Hes immediately above the Potsdam sandstone ; whilst the 

 main land is composed of g-neiss belonging to the Laurentian system. 



* Geol. Survey of Canada. Report for 1856. 



