1876.] 225 [Burbank. 



conglomerate is associated with a soft argillaceous and chloritic slate, 

 which was formerly quarried and used for gravestones. 



The beds of slate and conglomerate are interstratified, and coincide 

 in strike and dip with nearly vertical strata of crystalline gneiss in 

 which they are enclosed. The pebbles of the unaltered portion of 

 the conglomerate consist almost entirely of a gray quartzite. None 

 of these pebbles can have been derived from the rocks now existing 

 in the immediate vicinity. These conglomerates and slates appear 

 to form part of a continuous series with the enclosing strata of gran- 

 itoid gneiss. 



The series of specimens here exhibited shows a gradual transition 

 from a nearly unaltered conglomerate to a crystalline gneissoid rock. 

 Remarkable examples of flattened and curved pebbles are found in 

 the conglomerate. In some cases the pebbles are so much elongated 

 and curved as to give an agate like appearance to the surface of the 

 rock, as seen in the specimens shown. In many of the larger peb- 

 bles there appears a laminated structure which was doubtless pro- 

 duced by the same force which changed their external forms. 



The relation of these mechanically formed sediments to the adja- 

 cent crystalline rocks will be discussed more at length in a future 

 paper. 



Article IV of the Constitution was amended to read as 

 follows : — 



" Resident Members only shall be entitled to vote, to hold office, 

 or to transact business; Corresponding and Honorary Members and 

 Patrons may attend the meetings and take part in the scientific 

 discussions of the Society ; they may, however, on application, be 

 transferred to the list of Resident Members, by a majority vote of the 

 Council." 



February 2, 1876.- 



The President, Mr. T. T. Bouve, in the chair. Fourteen 

 persons present. 



The following paper was read : — 



The Affinity of the Mollusca and Molluscoida. 

 By W. K. Brooks, Ph.D. 



During last August and September I enjoyed, through the kind- 

 ness of Mr. Agassiz, an opportunity of studying the development of 



PKOCKEDINGS. B. S. N. H. — VOI/. XVIII. 15 APRIL, 1876. 



