110 Association of American Geologists and NaturaRsts. 



demonstrated that many species had been made from one, the dif- 

 ference of form having arisen from difference of age, locality, &c. 



Mr. L. stated, it so often happened in recent species, that the young 

 differed greatly from the adult, that he thought the geologist should 

 be cautious in coming hastily to conclusions which he might be com- 

 pelled to retract. He then exhibited specimens of the various stages 

 of growth of the Unio pUcatus, showing that the first and second growths 

 were really without plications — that after the second stage the first fold 

 began to appear, and subsequently the remainder of the shell was very 

 much plicate. In the tuberculate species this also happens, as was 

 shown by a specimen of Unio pustulalus ; the first growth having no 

 tubercle whatever ; the second growth having two tubercles, and each 

 stage of growth afterwards having two. He also instanced the genus 

 Melanin, as presenting difficulties in the various stages of growth, as 

 the characters of the whorls when the individual was young or half 

 grown was often entirely different, the marking on the superior half of 

 the whorls being frequently totally different from the inferior half. 



Friday, 2 o^clock, P. M. — The Standing Committee nomina- 

 ted as members : Prof. Ellet, South Carolina College, Columbia ; 

 Prof. L. R. Gibbs, Charleston College, S. C. ; John Vancleve, 

 Dayton, Ohio ; Prof. Alexander D. Bache, Washington ; Prof. 

 Joseph Henry, Princeton, N. J. ; Rev. John G. Morris, D. D., 

 Baltimore ; Peter Edwin Henderson, F. R. S., Civil Eng., York, 

 England; N. P. Ames, Esq., Springfield, Mass.; Prof. Loomis, 

 Waterville College, Maine ; Wm. O. Ayres, East Hartford, Conn. : 

 Frederick B. Leonard, M. D., Lansingburg, New York ; Prof. 

 Samuel St. John, Western Reserve College, Hudson, Ohio ; Prof. 

 Chase, Brown University, Providence, R. I. ; Edmund Ruffin, 

 Esq., Petersburg, Va. ; Lieut. Maury, U. S. Navy. 



Adjourned to 7^ o'clock, P. M. 



Friday, 7 J o'' clock, P. M. — The Association met pursuant to 

 adjournment. 



Prof. H. D. Rogers, chairman of the last annual meeting, de- 

 livered his anniversary address, " On the Progress of Geological 

 Science during the last three years in the United States," for the 

 first portion of which see the subsequent pages of this No. 



Saturday, May 1 1. — Dr. Locke in the chair. 



The order of business was read, and some minor points of bu- 

 siness detail were disposed of. 



Mr. Lawrence having informed the meeting that Messrs. Gales 

 & Seaton were ready to publish the proceedings of the Associa- 



