the Geology of the North Coast of the St. Lawrence. 97 



I shall describe one more proof of a change of level, which came under my own observation at 

 La Petite Riviere, near St. Paul's Bay. 



Between Cap Maillard and Cap de la Baie, near Quebec, the hills of gneiss, abounding in garnets 

 and magnetic iron ore, recede so as to form an irregular crescent, the interior of which is filled 

 with a low alluvial formation, not more than 20 feet above the rise of the highest tides. This 

 formation consists of clay thinly covered with sand, and contains many boulders principally 

 derived from the adjacent mountains. The clay is in thin, horizontal strata, and semi-indurated so 

 that it can be raised in large pieces, which are easily broken by the hand into rhomboidal slabs 

 from six inches to a foot in diameter. It abounds with impressions of rushes, partly filled with 

 and stained by, brown oxide of iron, derived, by filtration, from the neighbouring hills. It con- 

 tains also occasionally clam shells, similar to those existing in the river. 



Everything indicates a quiet deposition, when the waters of the river had a higher relative level 

 than at present. On this alluvial flat, the farms of La Petite Riviere are situated. At present 

 the St. Lawrence is fast destroying this alluvial formation, not by a rise in its waters, but by a 

 change apparently of the direction of the tidal currents, depending perhaps upon the formation of 

 shoals in other adjacent parts of the river. Every high tide, accompanied by a strong north-east 

 gale, washes away large portions of the fields, so that the inhabitants are driven to seek for fertile 

 soil among the hills. This gradual destruction has been going on for many years, as I was in- 

 formed by a Canadian, ninety years old, who had resided there from his youth. He pointed 

 out to me large boulders, now lying on the shoals, dry at low water, which he ploughed around 

 thirty or forty years before. 



The old church of La Petite Riviere has been washed down by the waves, and the present one 

 is likely to share the same fate, at no very distant period. The old church of Les Eboulemens 

 which was built upon a similar formation, has been also destroyed in the same manner. The 

 wall next the water has fallen, having been undermined by the waves, and trees now grow within 

 the other three, their roots assisting to preserve the ruin. 



Such are the indications of a change of level which have come under my own observation. I 

 must now conclude this subject with the following remarks. 



I cannot affirm positively that the heights of the terraces, in valleys and bays of the main land, 

 are exactly the same as those of the ancient sea beaches of the Mingan Islands, but there appeared 

 a very near agreement. 



It is certain that terraces of the same height extend over very large areas, and it appears ex- 

 tremely probable that the same agent may have simultaneously elevated these ancient alluvial 

 terraces, and the ancient beaches and natural columns of the islands. 



It is not easy to imagine any alteration in the level of the sea, within the Gulf of St. Lawrence, 

 without an equal change in that of the Atlantic Ocean. It is to volcanic agency, therefore, we 

 must look for the probable cause of the appearances which I have endeavoured to describe ; 

 and the probability of this inference is manifested by the fact, that the great agent alluded to is 

 still felt. Shocks of earthquakes are frequent at Murray Bay, Les Eboulemens, St. Paul's Bay, 

 and the adjacent country, of force sufficient, at times, to split walls, throw down chimneys, &c.* 

 The earthquake of 1663 is said to have lasted six months, and to have caused land slips and 

 other changes in the face of the country. It is to be regretted that there are no clear and detailed 



* For an account of the earthquake of 1791, see Lieut. Baddeley's Notes on the Geology 

 of St. Paul's Bay, Transactions of the Literary and Historical Society of Quebec, vol. ii. p. 83, 

 et seq, 1831. 



VOL. V. SECOND SERIES. P 



