XLIV THE ROYAL SOCIETY OF CANADA 



The softer overlying sedimentary rocks have been carved away and 

 the ancient core of resistant schists and the hard eruptive masses 

 have been disentombed and now form the highest peaks and ridges. 

 By this process of differential erosion the crest of the mountain range 

 has not only been greatly lowered, but has been shifted northwards 

 for several miles, as shown by transverse river valleys, so that the 

 once deeply buried harder rocks now rise as an almost impassable 

 wall near the north shore, while the softer materials slope more gently 

 toward the south. 



The physical contrasts between the two sides of the peninsula 

 have their origin, then, in geological phenomena that took place 

 more than one hundred millions of years ago; and the lives of the 

 people inhabiting the north and the south shores have been shaped 

 by these far-off events. 



Later Geological History of Gaspé 



While the main geographical features of Gaspé were fashioned 

 in the ways described the finishing touches were given to the land- 

 scape as we now see it in the latest geological periods, during the 

 Ice Age and the time of marine invasion. When the province of 

 Quebec was overwhelmed with an ice sheet thousands of feet thick, 

 the Shickshocks alone rose island like above the vast expanse of white 

 as ridges and hills of barren rock. From them local glaciers, like 

 those of the Rocky mountains, radiated out through the valleys and 

 joined the sea of ice that enclosed the range on all sides. The hollow 

 resting places of these local glaciers now form U-shaped valleys or 

 cirques, in which there is usually a lake or pond dammed by a moraine. 



While the great lobe of ice that filled the valley of the St. Law- 

 rence never rose high enough to cross Gaspé, it has left its mark on 

 the north coast in the form of innumerable blocks of granite, gneiss 

 and other rocks transported from the Laurentide hills east of Quebec. 

 The finest churches of Gaspé are built of these erratics and form col- 

 lections of Archaean rocks that are well worthy of study by the 

 geologist. 



The land sank under its great burden of ice, and when the load 

 was slowly removed by thawing toward the end of the Glacial period, 

 the sea returned at higher levels than now, carving or building the 

 terraces which are so marked a feature of the shores of the lower 

 St. Lawrence. As the land rose, terrace after terrace was formed, 

 until at last an equilibrium was reached at the present sea level. 



