6 ^'. 7^ 



THE 



AMERICAN 



JOURNAL OF SCIENCE 



Editor: EDWARD S. DANA. 



ASSOCIATE EDITORS 



Professors WILLIAM M. DAVIS and REGINALD A. DALY, 



OF Cambridge, 



Professors HORACE L. WELLS, CHARLES SCHUCHERT, 



HERBERT E. GREGORY, WESLEY R. COE and 



FREDERICK E. BEACH, of New Haven, 



Professor EDWARD W. BERRY, of Baltimore, 

 Drs. FREDERICK L. RANSOME and WILLIAM BOWIE, ^^ 



OP Washington. ...'■, „i., -^ • ^^'o./;/-,. '-<v 



FIFTH SERIES N^/onal ^^^^ 



VOL. II— [WHOLE NUMBER, CCII]. 



WITH PLA.TE I. 



NEW HAVEN, CONNECTICUT. 



1921. 



