1886.] NEW YORK ACADEMY OF SCIENCES. 39 



all waves in fluids, be followed bj others of less magnitude, until 

 the levels are all adjusted and the equilibrium is perfectly re- 

 stored. 



In conclusion, Mr. Chittenden maintained that the theory, 

 that there was a class of eartliquakes resulting from wave move- 

 ments of the fluid interior, accounted better than any other for 

 the successive shocks of diminished force; it conformed to the 

 evidence that true fissures extend through the crust, and that 

 volcanic vents communicate directly with the interior contents; 

 it was consistent with the inferred thickness and known flexi- 

 bility of the crust, and accounted for the large area of surface 

 sometimes involved. He did not contest the agency of shrink- 

 age as a powerful factor of earthquakes; he presented these con- 

 clusions of his own mind from an examination of the accessible 

 evidence, that there was a class of earthquakes resulting from 

 movements in the fluid contents below the earth crust, caused 

 by changes on the surface due to river transportation. 



Dr. N. L. Britton said he was informed that the series of 

 posts placed along the New Jersey coast to show changes of level 

 were not perceptibly changed by the recent earthquakes. 



Mr. H. T. Woodman and the President also spoke. 



November 8, 1886. 

 Stated Meeting. 



The President, Dr. J. S. Newberry, in the chair. 



Fifty-four persons present. 



Mr. B. B. Chamberlin exhibited pink dolomite from Mor- 

 risania, found near the north end of the Madison avenue 

 bridge. 



Mr. a. p. Bjerregaard stated that he had analyzed it and 

 regarded it as ferruginous dolomite or ankerite. 



Dr. J. J. Friedrich exhibited muscovite from West 87th 

 street, which was apparently folded and crushed as if by the yield- 

 ing of the strata. 



Mr, George F. Kunz showed the cast of a diamond from 

 North Carolina, which was probably the finest known from the 



