AMERICAN JOU RNAL 
SCIENCE AND ARTS. 
CONDUCTED BY 
PROFESSORS B. SILLIMAN, B. SILLIMAN, Jr., 
AND 
JAMES D. .DANA, 
IN CONNECTION WITH 
PROF. ASA GRAY, or CAMBRIDGE, 
PROF. LOUIS AGASSIZ, or CAMBRIDGE, 
DR. WOLCOTT GIBBS, or NEW YORK. 
SECOND SERIES. 
VOL. XXIII.—MA/Y, 1857. 
WITH FOUR PLATES. 
» 
NEW HAVEN: EDITORS. 
NEW YORK: G. P. PUTNAM & CO. 
——oOoOrrrees 
E. HAYES, PRINTER. . 
