UNSTRATIFIED DRIFT. 59 



found on the beach or in river beds. If our inquiries proceed a little 

 beyond a mere glance at these at first sight not very interesting 

 materials, we may discover that the large stones in the drift arc of very 

 different kinds. Some of them, perhaps the greater number, may be 

 of the same kind with the rocks occurring in situ in the vicinity. 

 Others are of kinds not found in place except at great distances. It 

 is farther observable that the ciay or sand containing large stones, is 

 not arranged in layers, but that its materials are confusedly intermixed. 

 The fine rounded gravel, however, is not only comparatively free 

 from large stones, but it is arranged in beds or layers, often with 

 bands of sand between. We shall also in some localities find beds of 

 fine clay containing marine shells, and sometimes, though rarely, com- 

 pressed peaty matter underlying the drift deposits. 



By studying the superposition of these materials, we may readily 

 arrive at the following arrangement of them in descending ordei', or 

 from the newer to the older : — 



1. Gravel and sand beds, and ancient gravel ridges and beaches, 

 indicating the action of shallow water and strong currents and 

 waves. 



2. Stratified clay with shells, showing quiet deposition in deeper 

 water. 



3. Unstratified boulder clay, indicating the united action of ice and 

 w^ater, 



4. Peaty deposits, belonging to a land surface preceding the deposit 

 of the boulder clay. 



As the third of these formations is the most important and generally 

 diffused in Acadia, Ave shall attend to it first, and notice the relation 

 of the others to it. 



The Unstratified Drift or boulder clay may be viewed as consisting 

 of a base or paste including angular and rounded fragments of rocks. 

 The base varies from a stiff clay to loose sand, and its composition and 

 colour generally depend upon those of the underlying and neighbour- 

 ing rocks. Thus, over sandstone it is arenaceous, over shales argil- 

 laceous, and over conglomerates and hard slates pebbly or shingly. 

 The greater number of the stones contained in the drift are usually, 

 like the paste containing them, derived from the neighbouring rock 

 formations. These untravelled fragments are often of large size, and 

 are usually angular, except when they are of very soft material, or of 

 rocks whose corners readily weather away. It is unnecessary to give 

 illustrations of these facts. Any one can observe, that on passing from 

 a granitic district to one composed of slate, or from slate to sandstone, 



