IV CONTENTS

 PLATE S. Emperador limestone member of Culebra formation on west bank of Panama Canal at canal station 1619, Canal
 Zone.
 9. Coralliferous limestone at base of La Boca marine member of Panamd formation on Rio Masambi 200 meters upstream from east bank of Panama Canal, Canal Zone.
 10. Strata in middle part of Gatun formation on east side of Gatun Third Locks excavation, Canal Zone.
 11. Toro limestone member of Chagres sandstone resting on marly siltstone in middle part of Gatun formation in
 road cut 3 kilometers southwest of Gatun, Canal Zone.
 12. Toro limestone member of Chagres sandstone in road cut 3 kilometers north-northwest of Gatun, Canal Zone.
 13. Chagres sandstone in road cut 3 kilometers south of Lagarto, Panamd.
 14. Middle and late Eocene mollusks from Gatuncillo formation.
 15. Late Eocene or early Oligocene mollusks from marine member of Bohio(?) formation and late Oligocene mollusks
 from middle member of Caimito formation in Gatun Lake area.
 16. Early Miocene mollusks from Culebra formation and La Boca marine member of Panams formation.
 17. Middle and late Miocene mollusks from Gatun formation.
 18. Middle and late Miocene mollusks from Gatun formation and early Pliocene mollusk from Chagres sandstone.
 19, 20. Middle Miocene mollusks from Gatun formation.
 21, 22. Middle and late Miocene mollusks from Gatun formation.
 23. Middle Miocene mollusks from Gatun formation.
 Page
 FIGURE 1. Map of Panamd showing principal areas of Tertiary marine sedimentary formations and area covered by plate I_ 11 2. Ungulate metapodial from transition zone between Culebra and Cucaracha formations -_------- 38 3. Reconnaissance geologic map of Caribbean coastal part of PanamA immediately west of Canal Zone ----_---__ 45 4. Correlation of Tertiary formations in different areas ----.. ----------- ------ ------------ 51