306 
GEOLOGY OF THE FOURTH DISTRICT. 
The strata are composed of alternating hard and soft materials, which unequally resist the 
influence of water and air. After a time the wearing action of the water below is so great 
that the base becomes too narrow to sustain the mass above, and it usually falls over on the 
seaward side, when it is soon dashed in pieces, and is removed by the waves. 
The “ Chimney rock,” below Jefferson, about two miles from the head of Seneca lake, 
is another example of this kind. A single block, originally one of a range separated by 
vertical planes, remains standing against the cliff, like a huge chimney upon the outside of a 
wall, to which it bears a fancied resemblance. 
The following is a sketch of this place : 
152. 
Where the water finds its way entirely around, the mass wears down much sooner than 
where one side continues attached to the main cliff. In some instances these blocks stand 
out along the line of the cliff in bold relief; and, from long weathering and wearing by the 
waves, have become rounded in outline, and the point of their attachment is constantly nar¬ 
rowed, until finally a separation takes place. The projecting edge overhangs the lake by 
several feet, and the water is so soon drained off through the smaller fissures that the larger 
trees near the edge die. 
153. 
