Morse J 240 [January 6. 



and Dr. Chas. T. Jackson, the opinion was advanced that these slides 

 might be partially due to the washing away of the substratum. If 

 this were so, we must suppose a chasm to be worn out, and such con- 

 ditions would be followed up by successive and repeated cavings in 

 of the embankments, and we should expect to see the widest area of 

 the shde bordering the river, while in this last event the area widens 

 as it recedes from the river, and the occurrence evidently occupied 

 but a short time. The softening of the substratum may be partially 

 due to the proximity of the river, but the almost impervious nature 

 of the clay tends to the accumulation of water, and boggy ground 

 above; in the cases above cited, the surface was wet and boggy, 

 and the drainage from these areas passed imder the sand, and over 

 the clay.^ As above remarked, the character of the substratum ob- 

 structs free drainage. Thus on. the occurrence of long continued 

 rains (a circumstance noticed in two of the above mentioned slides) , 

 the clay is reduced to a semi-fluid mass, and the slide occurs as a 

 natural sequence. 



If the causes of these slides be rightly interpreted, it follows that 

 where a clay bank of sufficient height borders a river, a slide may be 

 anticipated ; for the presence of a clay bank tends to the accumulation 

 of water upon its surface, and the river has cut, or is cutting away 

 the natural prop that would otherwise hold it in place. These slides 

 would have been disastrous to life had they occurred in inhabited 

 regions. In the case of the Ammoncongin land-shde, the damage 

 was estimated at over one hundred thousand dollars, and the check- 

 ing of the Cumberland paper mills, by which three hundred opera- 

 tives were thrown out of employment, and losses estimated at one 

 thousand dollars per day incurred. A gang of one hundred and fifty 

 men were required to aid in the opening of a new channel on the 

 intervale, and this has been accomplished. 



Since three of these slides had occurred within the space of thirty- 

 seven years, there was every reason to believe that traces of other 

 slides might be detected, and we now proceed to their examination. 



Mr. C. B. Fuller called my attention to a gorge below the one of 

 1868, which was evidently an old slide. Mr. George W. Hammond, 

 the agent of the mills, has called my attention to one revealed by the 



* In conversation with Mr. Mills, he expressed his opinion that the clay beneath 

 these slides was always in this semi-fluid condition, and that the river in its action 

 tapped these regions, as it were, allowing it to escape. 



