202 B. AVILLIS AMES KXOB, NORTH HAVEN, MAINE 



east to west. The present shores are of very youthful asj^ect, deeply 

 sinuous in water line, and not conspicuous!}^ remodeled by wave action 

 either through the development of sea cliffs or the construction of spits. 

 There is deep water close up to steep rocky shores, and shallows are 

 found chiefly off gently sloping lands. No wave-cut benches of rock or 

 sandbars interrupt the advance of the waves to the shore, though here 

 and there the surf plays about isolated rocks and skerries, which in con- 

 nection with the deep and crooked channels show how irregular is the 

 submarine surface. The subaerial surface exhibits closely corresponding 

 features of hollows, slopes, and hillocks, which are readily recognized as 

 forms sculptured by brooks and rivulets and modified by glacial erosion 

 and filling. The valleys are well adjusted to weak rocks or to shear 

 zones in massive rocks, and the hills are residual heights maintained by 

 harder masses. The maximum altitudes slightly exceed 200 feet on the 

 northern part of Yinal Haven, and on North Haven one knob, known 

 as Ames, is 150 feet in elevation ; in general, however, the higher lands 

 are from 100 to 140 feet above sea. Lower summits, as well as higher 

 ones, are, as a rule, bare rocks, which protrude through the glacial clay 

 and gravel deposits mantling the slopes. This mantle is so widespread 

 and its surface has been so little modified since the retreat of the ice, 

 that one is impressed with the recenc}' of that event. Neither waves 

 nor streams appear to have accomplished much in the post-glacial in- 

 terval. Distinct evidences of marine action at considerable height above 

 the present sealevel are therefore noteworthy as evidences probably of 

 Glacial or pre-Glacial times, and some such are presented in the follow- 

 ing account of Ames knob. 



Features of Ames Knob 



rock masses a^d relief 



The geology of the Fox islands has been studied by Mr George Otis 

 Smith, and to his account* we are indebted for the facts here made use 

 of. Ames knob and its slopes consist of andesite, which is in general 

 hard and compact. Even where the make-up of the rock is such that it 

 is ])roperly termed a volcanic conglomerate or breccia, the original frag- 

 ments are firmly cemented. About part of this hard mass of volcanic 

 material occur softer beds of like origin, in which tufiaceous rocks are 

 more common and lavas less so, while on the northern side of the knob 

 occur sedimentar}' rocks, consisting chiefly of shale and limestone. 



*The geology of the Fox islands, Maine; a contribution to the study of old volcanics. Skow- 

 liegan, Maine, 1896. 



