THE

AMERICAN JOURNAL

OF

SCIENCE AND ARTS.

EDITORS,

JAMES D. DANA, B. SILLIMAN, AND E. S. DANA.

ASSOCIATE EDITORS,

PROFESSORS ASA GRAY, WOLCOTT GIBBS AND
J. P. COOKE, JR., OF CAMBRIDGE,

PROFESSORS H. A. NEWTON, S. W. JOHNSON, G. J. BRUSH
AND A. E. VERRILL, OF NEW HAVEN,

PROFESSOR GEORGE F. BARKER, OF PHILADELPHIA.

THIRD SERIES.

VOL. XV.-[WHOLE NUMBER, CXV.]

Nos. 85-90.

JANUARY TO JUNE, 1878.

WITH TWO PLATES.

NEW HAVEN: EDITORS.

1878.