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UNITED STATES NATIONAL MUSEUM BULLETIN 215 



that the northern part of the slump-mass may in fact 

 be of the Olohorotalia fohsi fohsi zone. If so, it might 

 be related to the Olohorotalia fohsi fohsi beds and under- 

 lying pebble bed which are found farther south in the 

 type section. 



Stainforth (1948b, p. 1302) mentions an intraforma- 

 tional marl breccia within the Cacatro member, con- 

 sisting of angular pieces of greenish marl, mostly 

 polished or slickensided, in a marl matrix. During the 

 recent survey, 16 samples were collected from this 

 pebble bed between 848 and 913 feet, just south of the 

 "Cipero Nose" and resting on the Globorotalia fohsi 

 rohusta zone, consisting of single pebbles and matrix 

 containing small pebbles. Almost every zone from the 

 Globorotalia opima opima zone to the Globigerinatella 

 insueta zone is represented by these pebbles. The 

 matrix and pebble samples showed favmas ranging from 

 the Globorotalia opima opima zone to the Globorotalia 

 fohsi robusta zone. 



This pebble bed is now regarded as the base of the 

 large slump-mass extending from 848 feet to the north- 

 ernmost pebble bed at 406 feet. This interval contains 

 Stainforth's Zone II (between his Zone III and the 

 "Flat Rock tongue"). 



During the recent survey, a pebble bed was also 

 found to be present between Stainforth's southern Zone 

 II complex and his Zone III. This pebble bed marks 

 a stratigraphic break between the Globigerinatella in- 

 sueta zone and the Globorotalia fohsi fohsi zone. 



3. The northernmost portion of the section, where 

 the basal three zones (Globigerina ampliapertura zone 

 to Globigerina ciperoensis ciperoensis zone) of the Cipero 

 formation appear in normal succession. 



Stainforth (1948b, p. 130Q) divided the Cipero for- 

 mation at the type section into a lower (Zone I) Para- 

 dise member and an upper (Zones II, III) Cacatro 

 member, the two being separated by the "Flat Rock 

 tongue" which was regarded as being probably in nor- 

 mal stratigraphic position. Stainforth separated the 

 two members solely on the existence of the "Flat Rock 

 tongue" and not on hthological differences which he 

 considered neghgible. The study of the planktonic 

 Foraminifera of the "Flat Rock tongue" has now re- 

 vealed that the northern part of the tongue (northeast 

 of the pebble bed at 406 feet) is equivalent to the 

 Globigerina ampliapertura zone in age and apparently is 

 in normal contact with the overlying Globorotalia opima 

 opima zone. It has to be placed below Cushman and 

 Stainforth's Zone I, rather than between Zones I and 

 II as suggested by Stainforth. Southwest of the peb- 

 ble bed at 406 feet the "Flat Rock tongue" contains 

 other small and irregular pebble beds. Globigerina 

 ampliapertura Bolli, new species, and Globigerina parva 

 BoUi, new species, occur here together with such younger 

 forms as Globorotalia opima opima BoUi, new species, 

 new subspecies, Globorotalia fohsi Johsi Cushman and 

 Ellisor and lOrbulina sp. Here the rich orbitoidal 

 faunas mentioned by Stainforth are found. The peb- 

 ble beds and the heterogeneous faunas indicate that 



this portion of the "Flat Rock tongue" is a part of the 

 large slump-mass extending from 406 to 913 feet. 



The age of the "Flat Rock tongue" has been discussed 

 in several pubhcations and unpublished reports. It 

 was given as upper Eocene by several earlier authors. 

 Renz (1942) and Stainforth (1948b) attributed a 

 middle Oligocene age to it, based on the identification 

 of larger Foraminifera by B. Caudri (private reports) 

 and Vaughan and Cole (1941), and of the moUuscan 

 fauna by R. Rutsch (unpublished report). Stainforth 

 (1948b) admits that the evidence for placing the "Flat 

 Rock tongue" in the middle Oligocene is not entirely 

 conclusive and suggests as an alternative the possi- 

 bility that it could be an upfaulted block of the youngest 

 part of the San Fernando formation. This view brings 

 the stratigraphic position of the tongue much nearer to 

 the present interpretation. Stainforth placed the 

 bulk of Zone I in the lower Oligocene with the bottom 

 part possibly topmost Eocene and the upper part 

 middle Oligocene. Zone II was given a middle to 

 upper Oligocene age and Zone III a probable upper 

 Oligocene age. 



Although the basal part of the Cipero formation is 

 exposed in the type section, no contact with the under- 

 lying Eocene is visible. Such contacts may, however, 

 be studied further to the north, in the Vista Bella area 

 of San Fernando. Natural outcrops are scarce, but 

 much information has been obtained from lines of 

 augerholes and two shallow boreholes. About 500 

 feet of marls and marly clays or sUty, muddy marls of 

 the basal Cipero Globigerina ampliapertura zone are 

 found to rest on approximately 300 feet of Mount 

 Moriah silt of the upper Eocene San Fernando forma- 

 tion. Members of this formation may be developed in a 

 conglomeratic, sandy, sUty, glauconitic or reefal lime- 

 stone (Vista Bella Quarry) facies. In the Vista BeUa 

 area the Globigerina ampliapertura zone is overlain 

 normally by about 300 feet of marls of Globorotalia 

 opima opima and Globigerina ciperoensis ciperoensis 

 zone age. Although not well exposed, this section 

 appears to be one of the best in Trinidad for a study of 

 the basal Cipero and its contact with the uppermost 

 Eocene. 



Stamforth (1948b, p. 1297) states that the Cipero 

 formation rests basinward on the Hospital Hill marl, 

 which is now regarded as the top member of the Navet 

 formation. Although such contacts may occur, they 

 are not regarded as normal. Based on the occurrence 

 of planktonic Foraminifera, it is believed that the 

 Hospital HiU marl and the San Fernando formation 

 are not synchronous, but that the San Fernando forma- 

 tion is younger, representing the topmost Eocene and 

 thus lying between the Hospital HiU marl and the basal 

 Cipero. 



The lower Oligocene basal part of the Cipero forma- 

 tion is faunistically distinguished from the topmost 

 Eocene beds of the San Fernando formation by the 

 absence of Hantkenina, Globorotalia centralis Cushman 



