A NEEDED TERM IN PETROGRAPHY. 493 



meaning in chemistry of a totally different kind— that is, as the correlative of col- 

 loid. Petrograpliers can never hope to dispossess the chemists of their use of this 

 term even if it were desirable to do so. 



Feeling like others the need of a term to express the idea which has been men- 

 tioned above, the writer at the happy suggestion of Professor E. S. Dana, whom he 

 has consulted upon the subject, offers the word anhedron (from a^ privitive, and 

 'edpa^ a plane, meaning " without planes "), and by anhedron then is meant those 

 rounded or indeterminate forms without crystal planes in which minerals occur, 

 especially in igneous rocks. 



It will be noticed that the word is formed like a variety of well known terms, 

 such as octahedron, which are used in crystallography to express outward form. 

 Like them also it may be used in an adjectival manner, and we may speak of the 

 pyroxene of a certain rock as occurring in anhedrons or as having an anhedral 

 development. 



The last paper of the session was read by the author. 



NOTE ON THE OUTLINE OF CAPE COD 

 BY W. M. DAVIS 



Remarks were made by G. K. Gilbert, C. H. Hitchcock and the Presi- 

 dent. This paper is published in the Proceedings of the American 

 Academy of Arts and Sciences, 1896. 



Announcements were made of a reception at the residence of Dr Horace 

 Jayne and a lecture at the hall of the Academy of Natural Sciences by 

 Professor William B. Scott, both being complimentary to the several 

 visiting societies. 



The Society then adjourned until Friday morning. No evening session 

 was held. 



Session of Friday, December 27 



The Society convened in the geological lecture-room of the Department 

 of Arts at 10 o'clock a m, President Shaler in the chair. 



The Council's report was taken from the table and adopted without 

 debate. 



The Auditing Committee reported that they had examined the accounts 

 and vouchers of the Treasurer and had found them correct and agreeing 

 with the printed report. The report of the committee was adopted. 



LIX— BuLu Geol. Soc. Am., Vol. 7, 1895. 



