W. B. Dwight on a Subsidence of Land. 13 
of junction is very distinctly marked.” (N. Y. State Geol. Rep. 
Ist Dist., p.128.) This blue clay is also of very fine quality, 
and valuable for pottery : it contains more lime than the other, 
effervescing freely with acids, There is no appearance in this 
blue clay of consolidation into compact lamin, but there is evi- 
dence that it is brought into a semi-liquid condition by the pres- 
ence of water much more easily and thoroughly than the gray 
clay above. In the normal condition of the valley, the blue clay 
was not visible, being covered, even at the lowest points, by its 
lighter-colored associate. 
e terrace-level is cleared and tilled; the whole of the slope 
of the valley or ravine is, however, timbered with forest trees. 
n the morning of March 16th, 1861, Mr. Flansburgh, on 
visiting this part of his farm, to his utter amazement found his 
geography of the locality entirely at fault; a precipice, and a 
yawning gulf took the place of his wooded hill-slope ; his slop- 
Ing ground was nearly level, and his level sloping; a grove of 
fine trees stood waist-deep in a new pond of water, while the 
bed of his creek stood aloft high and dry; his trees were point- 
Ing in every imaginable direction, looking as if they had passed 
a hard night. 
~ The movement took place between 5 p.M., of the 15th, and 9 
A. M., of the 16th. There is no evidence that it attracted the 
end to ¢ e upper edge, of 
_ about one-third of the whole width of the detached mass. The 
_ Portion west of this line, consisting of the brow of the hill, 
