1871.] 87 [Niles. 



as proof of a sliding and slipping of parts. These features, however, 

 afford no evidence of present action. 



The phenomena observed seem, to me to establish the following 

 facts concerning the rocks at Monson: — 



1. That they are compressed at the present time with great force. 



2. That there is a lateral pressure exerted in northerly and south- 

 erly directions, but no indications of any acting in an easterly and 

 westerly course. 



3. That beds of very compact rock may be flexed and broken by 

 lateral pressure, as seen in the actual formation of anticlinals. 



4. That continued pressure does occasionally culminate in explo- 

 sions and movements of the rock. 



5. That even compact gneiss is, to a certain extent, compressible 

 and elastic. 



6. That whether lateral pressure originally brought the rock to 

 its present compressed state or not, it now keeps it in that' condition, 

 excepting, of course, where it has been artificially removed; then the 

 rock expands. 



I believe that these and similar phenomena, will throw important 

 light upon the more extensive folding, fracturing, and movement of 

 rocks, and the elevation of mountains; but the discussion of these 

 important relations is reserved with the hope of illustrating them by 

 further observations, in a future paper. 



Dr. C. T. Jackson and Rev. J. B. Perry mentioned in- 

 stances of similar expansion of solid rock masses which they 

 ascribed to changes of temperature. 



Dr. P. P. Carpenter, of McGill College, Montreal, made a 

 communication on the family of Chitons. 



January 18, 1871. 



The President in the chair. Forty-four persons present. 



The following paper was presented : — 



Experiment with the Poison op the Cobra de Capello 

 of India (JSfaja tripudians). By George Sceva. 



Jan. 8, 1871. One quarter of a grain of the dried poison, which 

 had been kept a little more than seven months, was dissolved in 



