the Geology of the North Coast of the St. Lawrence. 93 



The small columnar or prismatic structure was several times observed, precisely similar to spe- 

 cimens, which I have seen, from the limestone of Kingston in Upper Canada. At Betchewun 

 harbour, between Hunting island and the main, we noticed parallel, semi-cylindrical groovings in 

 the limestone, of various dimensions, and diagonal to the direction of the strata. At first we ima- 

 gined they had been produced by the attrition of boulders drifted by running water ; but further 

 observation induced us to think, they were due to structure. 



There is plenty of stone fit for the common purposes of building, but we saw none adapted for 

 ornamental architecture. Many of the strata are very hard, and although I do not think very 

 large blocks could be procured, yet the stone appears of excellent quality and stands the weather 

 well. 



Masses of flint were found several times on the beaches, and nodules of chert are not uncommon 

 in the limestone, particularly at Harbour island, Mingan, where the nodules are evidently derived 

 from organic remains. I found Orthoceratites, Encrinites, &c., completely converted into chert, 

 but with their shapes perfectly retained. In the greater number of these nodules, however, the 

 form of the organic body had been nearly obliterated, and in many cases it was not perceptible. 

 No metallic minerals were found in any quantity, but traces of lead, zinc, copper, and iron were 

 observed in all the islands. 



In some places there are few or no organic remains, but they are generally abundant. The 

 most common is a species of Ammonites, next Orthocera, and both were seen occasionally of very 

 large size. Encrinites and corals were also numerous, and several kinds of bivalve shells. Un- 

 chambered univalves were very rare, as we found only four or five specimens of two kinds. 

 Many of the fossils are similar to those in the limestones of Anticosti, Cape Gaspe, the neighbour- 

 hood of Quebec, Kingston in Upper Canada, and the Manatoulin islands in Lake Huron, a cir- 

 cumstance which induces me to think, that these limestones are of the same age. From the 

 organic remains, and all the strata being carbonaceous or bituminous*, I infer also that they are 

 analogous to the mountain limestone of England. 



7. On most of the Mingan islands the limestone cliffs have been broken by 

 the waves into columns of various shapes,, frequently resembling flower pots^ 

 or arched and perforated rocks^ &c. Plate V. fig. 2. 



It is extremely worthy of remark, that there are limestone columns and beaches of limestone 

 shingle, or gravel, exactly similar to those now forming, high up on the islands, from thirty to 

 sixty feet, at the lowest estimation, above the present level of the ocean at the highest tides, and 

 far back among the trees, in rear of the present sea beach. 



One of two hypotheses must, I think, be adopted to account for these appearances : — either the 

 general level of the ocean has fallen or the land has risen. If the latter supposition be the correct 

 one, and I think it by far more probable than the former, the raising of the land cannot have been 

 violently accomplished, for the strata are not disturbed, nor the columns thrown out of the per- 

 p3ndicular ; neither can it have been done all at once, but by a succession of gentle move- 

 ments at different epochs, acting uniformly over a great extent of country at the same time. 



This reasoning is founded upon the following appearances and observations : — The land cannot 

 have been raised by one great operation, because the columns and beaches are at different levels 

 on the same island ; and because on groups of flower-pot shaped, or other columns, there are 



* The limestone of the Manitoulin Islands is occasionally very bituminous. I have found 

 Orthoceratites from which, when broken, the bitumen flowed like tar. 



