BY
AMADEUS W. GRABAU

S.B., MASS. INST. OF TECHNOLOGY; S.M., S.D., HARVARD
PROFESSOR OF PALÆONTOLOGY IN THE GOVERNMENT UNIVERSITY
OF PEKING, CHINA, AND PALÆONTOLOGIST TO THE
CHINESE GROLOGICAL SURVEY

FORMERLY LECTURER IN MINERALOGY AND IN GEOLOGY IN TUFTS
COLLEGE, PROFESSOR OF MINERALOGY AND GEOLOGY IN
THE RENSSELAER POLYTECHNIC INSTITUTE, AND
PROFESSOR OF PALÆONTOLOGY IN
COLUMBIA UNIVERSITY

AUTHOR OF "PRINCIPLES OF STRATIGRAPHY," "GEOLOGY OF THE NON-
METALLIC MINERAL DEPOSITS OTHER THAN SILICATES," "NORTH
AMERICAN INDEX FOSSILS" (WITH H. W. SHIMER), "GUIDES
TO THE GEOLOGY AND PALÆONTOLOGY OF NIAGARA
FALLS, -- OF EIGHTEEN MILE CREEK, -- AND OF
THE SCHOHARIE REGION," ETC., ETC.

D. C. HEATH & CO., PUBLISHERS
BOSTON NEW YORK CHICAGO