GEOLOGY AND PALEONTOLOGY OF CANAL ZONE


 Larger Foramiaifera are the most abundant and widespread fossils in limestone and calcareous mudstone of the Gatuncillo formation. Loose specimens weathered out of both kinds of rock are most suitable for identification, as oriented thin sections can be prepared. At many localities these fossils weather out of hard limestone because they are silicified or partly silicified, whereas the limestone is not silicified. Plate 3 shows elective silicification and iron staining in a slab of limestone collected at locality 14. At locality 13 specimens of a small Lepidocyclina, probably L. pustulosa, are completely silicified and covered with beekite excrescences, producing fantastic effects. Though no larger Foraminifera from the Rio Casaya area appear in the


table of identified species, they were found in the area. The partly silicified limestone that yielded mollusks under acid treatment also yielded many specimens which probably are Lepidocyclina pustulosa. They are hollow, however, and therefore indeterminable. Float limestone in the Rio Casaya area contains somewhat silicified specimens of a saddle-shaped Lepidocyclina, probably L. chaperi.
 Samples of larger Foraminifera were collected at 27 localities. Those from 15 localities were selected, on a basis of favorable preservation and geographic and stratigraphic range, for study by W. S. Cole, whose report was published in 1953 (Cole, 1952 [1953]). His identifications are as follows:


Larger Foramiinifera from Gatuncillo formation
 [Cole, 1952 (1953), p. 4]


Yaberinella jamaicensis Vaughan Operculinoides floridensis (Heilprin) __ 
 jacksonensis (Gravell and Hanna)
 noodybranchensis (Gravell and Hanna)
 ocalanus (Cushman) _--- -_vaughani (Cushm an) _-_---_-_-_ ---_-_ ---_-_Nusmmnulites 2 strialoreticulatus L. Rutten Heterostegina ocalana Cushman ___-__ Fabiania cubensis (Cushman and Bermddez) Helicostegina soldadensis (Grimsdale) ----_-_ -----_ 

Lepidocyclina (Lepidocyclina) montgomeriensis Cole 
 (Pliolepidina) gubernacula Cole --_-__ 
 macdonaldi Cushman.__-_--- pustulosa H1. D ouvil .6 ..- _-_- __- __pustulosa tobleri H. Douvil6 __ ___- _____(Nephrolepidina) chaperi Lemoine and R Douvi6-


Helicolepidina spiralis Tobler Asterocyclina georgiana (Cushman) 
 mariannensis (Cushman) --minima (Cushman)___-_----Pseudophraginia (Proporocyclina) flintensis
 man)_ --------


(Cush-


Madden basin


1 2 1 4 110


 Rfo Rfo GainQuebrancha synclina Rfo Agua Agua Frijol boa sucia area salud area area
 Saia a r s,, e a

 11 19 22 23 26 27a 28 29 33 37




- ---- -- ------- - - --- - X - -- 


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 --- - X 
X -_ X -x X - X
- --- -x- --- --S----x-- ------- ---- 
- ---- X 
X x x x -_- --- X X ---- x
x X X ---- -_-- X X X
 -- X X --- --- - -- -- -- X - -- X
 X X X X -----x X - X x X

 -X----- X --X X --- 
 x X X ---- X ---- X ------ -- ---- --- X ---- ---___ _- - X X x ----


I The locality numbers in Cole's publication are field numbers. For correlation with report numbers of present report see p. 112-116.
2 Cited by Colo as Camerina.


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