Field Book
PENNSYLVANIAN PLANT FOSSILS OF ILLINOIS
Charles Collinson
Romayne Skartvedt
Illinois State Geological Survey
Educational Series 6
STATE OF ILLINOIS
DEPARTMENT OF REGISTRATION AND EDUCATION
First edition 1960
Reprinted 1966
ILLINOIS STATE GEOLOGICAL SURVEY
URBANA ILLINOIS
John C. Frye, Chief
Printed by Authority of State of Illinois, Ch. 127, IRS, Par. 58.25.
Field Book
PENNSYLVANIAN PLANT FOSSILS OF ILLINOIS
Charles Collinson
Romayne Skartvedt
Illustrations by Marie E. Litterer