200 . Tertiary. 



often arranged in heaps and hollows, or conical and irregular eleva- 

 tions with corresponding depressions. A class of alluvial ridges found 

 in great abundance in Maine are called horsebacks. Sea beaches and 

 sea bottoms are found 150 feet higher than the ocean level, and con- 

 taining littoral shells. Fossiliferous marine clays form almost a con- 

 tinuous iaelt, extending up the rivers to about this height above the 

 ocean. Alluvial terraces are those banks of loose materials, generally 

 unconsolidated, which skirt the sides of the vallej's about rivers, ponds, 

 and lakes, and rise above one another like the seats of an amphithea- 

 ter. 



Prof. Edward Hitchcock* collected about 300 measurements of the 

 drift stripe found in the State of Vermont. The course varied from, 

 north 70 deg. east to north 80 deg. west. It seems to have been rare 

 to find the strise, at any two points, exactly agreeing in direction, 

 though he divided the predominant courses into three divisions, viz: 

 1, From the northwest. 2. From the northeast. 3. From the north. 

 The strise differ in size from the finest scratch visible, up to a furrow a 

 foot deep. 



Prof. J. W. Dawsonf described the Post-pliocene deposits at Murray 

 baj', on the St. Lawrence riyer, 90 miles below Quebec, where thej- con- 

 sist of the Leda clay and Saxicava sand. There are several terraces 

 at this place, varying from 30 to 132 feet above the sea level, but the 

 highest true shore-mark observed, is a narrow beach of rounded pebbles 

 at the height of 326 feet. This beach appears to become a wide terrace 

 further to the north, and also on the opposite side of the bay. It pro- 

 bably cori-esponds with the highest terrace observed b3' Sir W. E. 'Lo- 

 gan, at Bay St. Paul, and estimated by him at the height of 360 feet. 

 The two principal terraces at Murray bay correspond nearly with two 

 of the principal shore-levels at Montreal and in various parts of Cana- 

 da, where two lines of old sea beaches occur at about 100 to 150 feet, 

 and 300 to 350 feet above the sea, though there are others at different 

 levels. 



Dr. F. V. HaydenJ sketched the geology of the countrj^ about the 

 headwaters of the Missouri and Yellow Stone, and said that through- 

 out the Wind river valley there is a series of beds of great thick- 

 ness intermediate in their character between the true lignite beds 

 and the White river Tertiary deposits. They extend from Willow 



*.Rep. on the Geo. of Vermont, vol. i. 



+ Can. Nat. and Geol., vol. vi. 



X Am. Jour. Soi, and Arts. 2d ser., vol. xxxi. 



