150 NEW YORK STATE MUSEUM 



noting the overhanging turf and tree roots (figure 3)". Recent rock 

 falls may also be noted at a and b (figure 4). A direct comparison 

 should be made between the cliff itself and the view of it which 

 is here presented. 



The rock which forms the south cliff offers very marked contrasts 

 to the Trenton which rests against it. It has successfully resisted 

 the same influences which are so rapidly destroying the Trenton 

 beds. The southern wall belongs to the Chazy formation, older than 

 the Trenton. This stone is so good for building purposes that it 

 was once extensively quarried here. When the United States 

 spent a million or so in building Fort Montgomery (on the Canadian 

 side of the United States boundary) the Cliff Haven stone was 

 chosen on account of its excellent quality and many a fine block 

 was taken from the now abandoned quarry just around the point 

 shown in figure 2 and loaded on boats which were tied to a dock 

 built for that purpose just outside the same point. 



The answer to our first problem should now be apparent. The 

 softer rock has been eaten away by the " tooth of time " while the 

 harder rock has offered more effective resistance to all eroding 

 agents. The bay and the protecting wall to the south are the result. 

 If further evidence is desired one has but to ask why an artificial 

 stone wall was built along a portion of the beach front and why to 

 the north of this several breaches in a boulder-built wall were 

 repaired and further fortified in the fall of 1916. The effects of 

 wave action on a weak shore line are manifested in numerous local- 

 ities between Plattsburg and Cliff Haven. In many places the 

 Delaware and Hudson Railroad has had to build a sea wall and 

 residents of Plattsburg can remember recent landslides which carried 

 forested portions of the higher banks down to the lake level, where 

 the waves of new storms could take care of the debris. 



As soon as the student gets an answer to his first question he will 

 be ready to ask another. How fast has the Trenton rock been 

 receding and where was the shore line of this bay when the dis- 

 coverer, Champlain, first passed through the lake? This ques- 

 tion will not be so easily answered as the first. Quantitative 

 analysis is always more difficult than qualitative. The former, how- 

 ever, usually yields results of the greater value. We may here 

 point out one or two lines of investigation that will yield an answer 

 to this question. 



At a in figure 3 we may note what remains of a small tree whose 

 age, at the time its trunk was lopped off b}- an axe, could be readily 

 determined by counting its annual rings. When this tree started 



