GEOLOGY AND PALEONTOLOGY OF CANAL ZONE


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Figure 2.-Ungulate mctapodial from transition zone between Culebra and Cucaracha formations. Univ. Calif. Mus. Paleontology 37363, natural size. 11, 4. Lateral viewNs
 2. Front view 3. Distal view
 5. Posterior view


including the Tampa limestone of Florida, which also contains no orbitoids. None of the mollusks in the preceding list suggest species that are only of greater age than disputed Oligocene or Miocene, whereas Littorina aff. L. angulifera, Pachycrommium? cf. P. guppyi, and Turritella cf. T. subgrundifera suggest species that are only of younger age than disputed Oligocene or Miocene. Whether the Culebra formation is to be assigned to the late Oligocene or early Miocene is part


of the larger question of whether the Aquitanian stage of western Europe is late Oligocene or early Miocene, for the Culebra and correlated formations are the essential equivalent of the Aquitanian. It has long been recognized that the marine type Aquitanian of the Aquitaine basin contains an early Miocene fauna. The argument concerning the age of the Aquitanian centers on the Oligocene aspect of the mammalian fauna in nonmarine strata that are thought to be the equivalent


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