SOME LOCAL DETAILS. I35 



beds present the exceptional feature of resting on a soft 

 and decomposed shale (Utica shale). This rock might 

 indeed be mistaken for drift but for its stratification, 

 and it must have been decomposed to a great depth by 

 sub-aerial action and subsequently submerged and covered 

 by the Pleistocene l)eds. Its preservation is the more 

 remarkable that tlie clay overlying it contains very large 

 Laurentian boulders, which must have been quietly de- 

 posited by floating ice. Only a few shells of Tellina 

 Grmyilandica were observed in these clays. 



The remarkable series of terraces seen at this place, 

 and noticed in chapter second, rising to 900 feet in height, 

 are all cut out of the Pleistocene beds and decomposed 

 shale, and even the highest presents large boulders. In 

 examining such terraces it is always necessary to distin- 

 guish between the clays out of which the terraces have 

 been cut and the more modern deposits resting on the 

 terraces. Both may contain fossils, but those of the 

 original clay are in . this region mostly of deeper water 

 species than those in the overlying superficial beds. 



I attribute the preservation of the thick beds of boulder- 

 clay and the decomposed shale at Les Eboulements, to the 

 fact that no transverse valley exists here, and that a point 

 of high Laurentian land projects to the north-east, so as 

 to shelter this place from forces acting in that direction. 

 I have observed this appearance on the lee or south-west 

 side of other projecting masses of hard rock, and as the 

 decomposed shale must be a monument remaining from 

 the Pliocene elevation of the land, it shows that no 

 ])owerful eroding force had acted between that time and 

 the period of the KE. arctic ice-laden currents. 



It is perhaps deserving of notice that tlie tliick beds of 

 soft material at Les Eboulements have been cut into 



