GEOLOGY


Pleurostomella alterans Schwager
 bierigi Palmer and Bermddez
 ef. P. naranjoensis Cushman and Bermddez Pseudoglandulina conica (Neugeboren)
 sp.
Pullenia cf. P. quinqueloba (Reuss) Quinqueloculina ef. Q. maculata Galloway and Heminway Robulus ef. R. alazanensis (Cushman)
 artirolatus var. lexanus (Cushman and Applin)
 iotus (Cushman)
 sp.
Schenckiella sp.
Sigmomorphina ef. S. trinitatensis Cushman and Ozawa Siphonina tenuicarinata Cushman Siphonodosaria nuttalli var. gracillima (Cushman and Jarvis)
 sp.
Spiroloculine texana Cushman and Ellisor Uvigerina rf. U. adelinensis Palmer and Bermddez
 chirana Cushman and Stone
 gardnerae var. nuttalliana Howe and Wallace
 spinicostata Cushman and Jarvis
 sp.
Vaginulina sp.
Vaginulinopsis alazanensis (Nuttall) Virgulina ef. V. dibollensis Cushman and Applin Vulvulina pachyheilus Hadley
 Messrs. Renz and Bermudez prepared the following comments concerning these fossils:
 The Foraminifera collected at locality 39 are of early Oligocene age. They have distinct affinities with the early Oligocene faunas of the Alazdn formation (or Huasteca formation) of the Tampico region in Mexico (Nuttall, 1932), the Tinguaro formation (or Finca Adeline mar!) of Cuba (Bermddez, 1950, p. 264-270), and Zone I in the lower part of the Cipero formation of Trinidad (Cushman and Stainforth, 1945).
 Larger Foraminfera.-The upper part of the Bohio on Barro Colorado Island yielded Heterostegina antillea, Archaias compressus, Lepidocyclina canellei, L. giraudi, L. waylandvaeghani, L. vaaghani, Miogypsina antillea, and M. gunteri (Cole, 1957). Cole identified the following species, which were collected at localities 43 and 45 in the upper part of the formation in the Pacific Coastal area:

Larger Foraminifera from upper part of Bohioformation in Pacific coastal area.
 [Cole, 1952 (1953), p. 6] Localitie

Heterostegina antillea Cushman-_---------.------ X X
Lepidocyclina (Lepidocyclina) parvula Cushman_-__-- X --waylandvaughani Cole ------ -- X
 yurnagunensis Cushman----------------- X -~yurnagunensis morganopsis Vaughan---------- X X
 (Nephrolepidina) vaugtani Cushman------------ -_ X
 (Eulepidina) favosa Cushman_----------- X X
 gigas Cushman -------------------------- X --Mollusks.-The upper part of the Bohio formation in the Pacific coastal area yielded pectinids, but no other mollusks. On Barro Colorado Island the upper part of the formation yielded marine mollusks at two


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localities (42d, 42i) and a mixture of marine, brackishwater, and fresh-water mollusks at a third locality (locality 42f). Howe recorded the presence of marine mollusks in carbonaceous sandstone penetrated in a core hole at the French lock site near Barro Colorado Island (Howe, 1908, p. 220-221).
 The fossils from Barro Colorado Islands, all of which occur in subgraywacke interbedded with conglomerate, were received too late to be included in the systematic descriptions of chapter A of the present report. The species in the families covered by chapter A are as follows:

 Mollusks from upper part of Bohio formation on Barro Colorado
 Island (Trochidae to Turritellidae)
 Localies
 424 42f 42g
Solariella n. sp., cf. S. depress Dall --- ---- X 
Neritina sp_ - -- - - X Hemisinus (Longiverena) n. sp., cf. I. atriformis
 Cooke-..--------- -- _-- X 
 Crepidula? sp------------------------------- --X
 Notica (Naticarius) sp--..-- - - ?
 Polinices 9-------- -- ?
 Sinum sp --------------------<
 Gl bularia (Globularia) aff. G. flscleri (Dall) -? Pachycrommium aff. P. guppyi (Gabb) _------ X Turritella ef. T. altilira Conrad - ------- X
 n. sp., aff. T. venezuelana Hodson ------- X -In chapter B of the present report, it is proposed to describe the new species in the preceding list and to redescribe the species identified as Globularia aff. G. fischeri. The last species mentioned is abundant at locality 42d and is the same as that from the Caimito and Culebra formations described under the same name on page 94. The fossils found on Barro Colorado Island are of late Oligocene age.
 Age.-The basal part of the Bohio in the Quebrancha syncline contains smaller Foraminifera of early Oligocene age and the upper part of the formation in the Pacific coastal and Gatun Lake areas, respectively, contains late Oligocene larger Foraminifera and mollusks. Whether the formation represents so great a time span in each of the areas where it crops out is not known at present. It represents, however, more than the early Oligocene age previously suggested (Woodring and Thompson, 1949, p. 228). That it does not include all of the Oligocene is shown by the late Oligocene age of the overlying Caimito formation.
 The larger Foralninifera in the upper part of the Bohio formation of the Pacific coastal area represent the widespread Caribbean Eulepidina fauna. That fauna and the Antiguan coral fauna that accompanies it at many localities is traditionally assigned to the middle Oligocene, because Vaughan correlated the Caribbean deposits with the Rupelian of northeastern Italy on the basis of the corals and because he thought a middle