Post-Glacial Terraces of Anticosti Island. 275 



rence, proving that these terraces have been formed since 

 Champlain time. 



Deposits of post-ChampIam time. — At many points 

 along the coast are the stratified sands and gravels to 

 which reference has been made. At Southwest Point 

 these deposits are truncated by the 65-foot terrace, at 

 Caplin River an 85-foot terrace is cut across them, and 

 at Cape Ann the 74-foot terrace does the truncating. At 

 the last named place the many shells of MytUus edulis and 

 Mya arenaria occurring throughout the deposit — species 

 now li^dng in abundance along some portions of the shores 

 of the island — show that these deposits are of an age 

 younger than those laid down during the Champlain sub- 

 mergence. The highest point where these gravels have 

 been observed is about 100 feet, and every terrace up to 

 the height of their observed occurrence passes from them 

 to bed rock without appreciable break in flatness. 



Age of the river valleys. — The river valleys are of two 

 distinct types. Nearly all the smaller streams flow in 

 rock-floored, narrow valleys and the greater portion of 

 these reach the sea over rapids or a fall, the streams not 

 being able to cut. downward as rapidly as the sea cuts 

 landward. Other streams have wide valleys and flow 

 over floors of gravel and sand, attesting to the presence of 

 an older valley floor beneath. The latter type is illus- 

 trated by parts of the Caplin, Yaurial, Jupiter, Fox, 

 Otter, and Salmon River valleys, which are in that stage 

 of the erosion cycle verging very closely on maturity. 

 The Caplin River has a broad flood-plain for such a small 

 stream and as a general rule the valley slopes are gentle. 

 Near the mouth, however, the valley narrows and the 

 stream flows to the sea between high cliffs, which are com- 

 posed of bed rock, but behind which there are cliffs com- 

 posed of glacial and stratified gravel. This suggests that 

 the stream has made a new entrance to the sea, and as the 

 shore to the west consists of gravel cliffs for fully a half 

 mile it is probable that the older valley lies hidden there. 

 These older valleys are of pre-giacial origin, as shown by 

 their aspect of maturity, the glacial deposits which are in 

 them, and the glacial striae which have been seen on the 

 Cape and Vaurial rivers. As no Tertiary deposits have 

 been seen in any of them, it is assumed that this region 

 was as high in pre-Glacial time as it is at present, with 

 the probability that it was somewhat higher. The 



