Corals from Gatuncillo formation
 [Identifications by J. I. Wells


 Lepidocyclina pustulosa, L. macdonaldi, and L. chaperi are abundant and widespread. Discocyclinids (Asterocyclina and Pseudophragmina) were collected at 7 of the 15 localities, Helicolepidina spiralis at 6 localities, Fabiania cubensis at 6, Helicostegina soldadensis at only one. Yaberinella jamaicensis was found in the basal part of the formation (localities 1, 1a), associated with Fbiania cubensis. Nummulites striatoreticulatus is a relatively large nummulite for an American species. Operculinoides is extraordinarily abundant at locality 10.
 According to Cole (1952 [1953], p. 4-5), the larger Foraminifera of the Gatuncillo formation are dominated by species characteristic of the upper Eocene rocks of Trinidad and Florida. He also pointed out that two of the species (Yaberinella jamaicensis and Fabiania cubensis) are recorded only from the middle Eocene, but that there are good grounds for considering that the former ranges upward into upper Eocene in Jamaica and the latter into upper Eocene in Cuba.
 Corals.-Corals are fairly common in limestone, for the most part hard limestone that yields only random sections. Specimens that weathered out of softer marly limestone and calcareous mudstone were collected at five localities. Such fossils, which generally are poorly preserved, were found to be abundant only at locality 11, where slabs of limestone from a partly demolished hill are disintegrating. The collections were examined by J. W. Wells, who identified the following species:


Heliopora sp - Astrocoenia incrustans Duncan Astreopora n. sp Diploastrea n. sp. aff. D. crasso ellata
 (Duncan).-- -.Goniopora aff. G. taberi Wells Esriteo (Synaroes) a. sp------Favia of. F. weisbordi Wells Colpophyllia sp.-- Antillia cf. A. hadleyi Wells Millepora aff. M. alcicornis Linn6-----


 Localities

 Rio
 Madden Aga
 basin Oaoia
 area

8 1 12 16 26

 x------ ---xx
 -----------X

 x

 ?x------x --------x
 x ---x- ------


 Wells reports that the new species of Diploastrea is closely allied to the widespread late Oligocene D. crassolamellata and that the fossils from locality 11 constitute the first record of a pre-Pleistocene alcicornislike Millepora in America. He points out that most of the other species show close relationship to upper Eocene Cuban corals and a less marked relationship to middle Eocene corals from St. Bartholomew.


Mollusks froom Gatuncillo formation (Neritidae to Turritellidae)


Velates perverse (Gmoelin), subsp.? Hannatoma? cf. H-. emendorferi OlssonXenophora sp__--- --- ---__Hipponix sp ----------------------Calyptraea cf. C. aperta (Solander) Polinices? sp -------Neverita? sp -------Sinum sp_ -------Anarellina? sp -----Pachycrommiun, solenaeun?, Woodring, n. sp Turritella cf. T. carinata Lea
 ef. T. samanensis Olsson--. .
 sp. . . . .


6 7 9 11 12 16 32 X X X X --------x ---- x- ---- x --- -_- X --- 

 ___- X X X X I- -


Madden basin Rfo Frijol Casaarea ya area


34 1 38


GEOLOGY


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