TY  - BOOK
AU  - Petersen,Morris S
AU  - Rigby,J.Keith
TI  - Interpreting earth history: a manual in historical geology 
SN  - 0697050882
PY  - 1990///
CY  - Dubuque, Iowa
PB  - Wm C. Brown Company Publishers
KW  - Historical geology
ER  -