Peat Beds of Anticosti Island. 67 



and shales witli an approximately level eroded surface, the 

 beds dipping southward from loss than one to about six degrees. 

 Lying upon these strata in limited areas, but so far as known 

 to the writer, on the south side only, are stratified beds of 

 Pleistocene or more recent clays that are of marine origin, as 

 indicated by the presence of Mya arenaria in abundance. A 

 small angular unconformity, difiicult to determine on small 

 exposures, separates the two deposits. 



Overlying portions of these clay deposits conformably, so 

 far as known, are beds of stratified sand and gravel ranging in 

 some places up to more than fifty feet in thickness and holding 

 at different horizons lenses of clay. In some localities the sand 

 apparently rests on the limestones. Pebbles and bowlders of 

 glacial origin are present in both clay and gravel. 



Overlying the clay, gravel, and sand, and the limestones 

 where these are wanting, is a thin veneer of limestone gravel, 

 which is apparently of beach origin. Overlying this are the 

 peat beds producing another unconformity. These two uncon- 

 formities would, after burial, be difficult to detect at small 

 exposures, unless such were transverse to the old cliffs, and 

 fossil evidence would be the chief criterion for their deter- 

 mination. 



Marine Fossils in the Peat Beds. — On the lowest terrace, 

 shells of marine organisms, such as sea-urchins, fragments of 

 lobsters and crabs, gastropods, etc., are exceedingly common ; 

 being brought there by birds, chiefly crows, and more rarely, 

 but in greater numbers, by waves of storms. Many examples 

 of tiie latter case can be seen at different points along the south 

 shore, where hundreds of sea-urchins have been washed upon 

 the seaward edge of the marsh.* These must exist in the peat 

 beds of the lowest terrace, and as each of the higher terraces at 

 one time lield the position of the now lowest terrace, they 

 should also be found in them although none were seen. 



Conditions of Formatioyi. 



Character of the Vegetation. — The conditions that have per- 

 mitted the development of these extensive peat deposits 

 without an underlying soil are due to a combination of con- 

 ditions none of which are uncommon. The greater portion of 

 the island is covered with a low, dense, chiefly coniferous forest 

 growth, so dense in many places as to be almost impenetrable. 

 The absence of a soil does not permit the trees to gain a firm 

 foothold, while the vast amount of water in the substratum 

 has forced a horizontal development of roots. The foothold 

 of the trees is, therefore, in most cases a very precarious one. 

 The result is that the winds, always prevalent and usually 

 strong, blow most of them down before a great height is 



* On the marsh about six miles west of Chaloupe Creek bushels of the 

 common sea-urchin {Strongylocentrotus drobaehiensis) were seen. 



