David Fm

• Type Locality: Terry (1956). In western Panama, recognized Eocene begins three miles north of David, the capital of Chiriqui Province. This is about 100 miles west of the nearest Eocene, on the shore of Montijo Bay. The intervening sedimentary area of Chiriqui and Veraguas is surfaced with Oligocene and Miocene, and the Eocene may underlie them, but is not known to outcrop. The well-known David Eocene exposure near km 12 on the Chiriqui National Railway is in a much-faulted area with tepid sulfur springs which have created a swamp surrounding the small outcrop of orbitoidal limestone from which Lepidocyclina panamensis, L. duplicata, and L. macdonaldi have been identified. Farther west, for a distance of five or six miles, a more complete section is exposed on various tributaries of Río Platanal; and near the Costa Rica border, on the Río Blanco de Brenon, a small tributary of the Chiriqui Viejo, an apparently complete section of late Eocene can be seen in the axial part of a large anticline. Three limestone beds, separated by coarse barren sandstones, yielded the following:
• Basal bed (lying on andesite) - Eodictyoconus, Camerina, Heterostegina, Discocyclina sp. near D. minima Cushman, Lepidocyclina 2 spp.
• Bed 2 - Discocyclina sp., Lepidocyclina trinitatis (?), Lepidocyclina (Nepthrolepidina) sp., Lepidocyclina sp. Possibly a fourth species of Lepidocyclina.
• Bed 3 - Lepidocyclina trinitatis (?) and L. (Nephrolepidina).

Above Bed 3 is another barren sandstone and then a conglomerate with lime cement, carrying Lepidocyclina gigas and marking the base of the Oligocene.

References: See alternative information at “Additional Information”.

Synonym: David foraminiferal limestone (Olsson (1942b, pg 234 & 236)), Davidkalk = David Limestone

In Chiriqui Province.

In Costa Rica, the coastal range of Fila Costeña exposes the largest shallow-marine carbonate platform sequence known in te country: the "Fila de Cal" limestones - named the David Fm in Panama (Bolz et al. (2018)). Eames et al. (1968) considered some equatorial sections of specimens from samples 2 miles north of David (Panama) that Cole (1960, pl. 3, Figure1) previously illustrated to probably belonging to the subspecies panamensis rather than L. (Pliolepidina) tobleri (s.s.). As authors stated, L. tobleri subsp. panamensis Cushman differs from L. tobleri s.s. in having a more inflated test and a large pliolepidine embryo showing a thinner wall. These deposits belong to the David Fm (Domínguez (1978)).

Synonym: David foraminiferal limestone (Olsson (1942b, pg 234 & 236)), Davidkalk = David Limestone

Lithology and Thickness: Consists of fossiliferous limestone and shale separated by barren sandstone.

Lithology-pattern: Sandy limestone

Relationships and Distribution:

Lower contact: Bucarú Fm (obsolete name)

Upper contact: Majagua Fm (obsolete name)

Regional extent: Chiriqui Province

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Fossils: Though the formation contains foraminifera, mollusks, and echinoids, only the foraminifera are recorded: Lepidocyclina macdonaldi, L. pustulosa («panamensis» and «duplicata»), and Asterocyclina minima. Woodring (1960). Shallow-water Eocene carbonate deposits with rich assemblages of larger benthic foraminifera are seen, although they are not as continuous through time. The type section of the Upper? Eocene David Fm of southwestern Panama has yielded the larger foraminifera Lepidocyclina panamensis, L. duplicata and L. macdonaldi, and the probable extension of this limestone unit to near the border with Costa Rica contains a richer assemblage. Bundschuh et al. (2012).

In Chiriqui Province.

In Costa Rica, the coastal range of Fila Costeña exposes the largest shallow-marine carbonate platform sequence known in te country: the "Fila de Cal" limestones - named the David Fm in Panama (Bolz et al. (2018)). Eames et al. (1968) considered some equatorial sections of specimens from samples 2 miles north of David (Panama) that Cole (1960, pl. 3, Figure1) previously illustrated to probably belonging to the subspecies panamensis rather than L. (Pliolepidina) tobleri (s.s.). As authors stated, L. tobleri subsp. panamensis Cushman differs from L. tobleri s.s. in having a more inflated test and a large pliolepidine embryo showing a thinner wall. These deposits belong to the David Fm (Domínguez (1978)).

Age:

Age span:

Beginning stage: Bartonian

Fraction up in beginning stage: 0

Beginning date (Ma):

Ending stage: Chattian

Fraction up in ending stage: 0

Ending date (Ma):

Depositional setting: shallow-marine carbonate platform

Depositional-pattern:

Additional Information

• Sapper (1937).
• Olsson (1942b). David Fm applied in broad sense to the younger upper Eocene rocks of Panama, consisting generally of foraminiferal limestones in their entirety or of shale and sandstone formations in which the limestones may be entirely missing or restricted to reeflike masses. In vicinity of David and Brenon, occurs above Bucarú Fm; in Veraguas and Los Santos area occurs below Tonosí limestones.
• Cooke (1948). Though this is believed to be the first published record of Eocene echinoids in Panama, the collections in the United States National Museum include a few specimens collected many years ago in Los Santos Province, evidently from late Eocene limestone assigned to the David Fm by Olsson (1942b).
• Terry (1956). In western Panama, recognized Eocene begins three miles north of David, the capital of Chiriqui Province. This is about 100 miles west of the nearest Eocene, on the shore of Montijo Bay. The intervening sedimentary area of Chiriqui and Veraguas is surfaced with Oligocene and Miocene, and the Eocene may underlie them, but is not known to outcrop. The well-known David Eocene exposure near km 12 on the Chiriqui National Railway is in a much-faulted area with tepid sulfur springs which have created a swamp surrounding the small outcrop of orbitoidal limestone from which Lepidocyclina panamensis, L. duplicata, and L. macdonaldi have been identified. Farther west, for a distance of five or six miles, a more complete section is exposed on various tributaries of Río Platanal; and near the Costa Rica border, on the Río Blanco de Brenon, a small tributary of the Chiriqui Viejo, an apparently complete section of late Eocene can be seen in the axial part of a large anticline. Three limestone beds, separated by coarse barren sandstones, yielded the following:
• Basal bed (lying on andesite) - Eodictyoconus, Camerina, Heterostegina, Discocyclina sp. near D. minima Cushman, Lepidocyclina 2 spp.
• Bed 2 - Discocyclina sp., Lepidocyclina trinitatis (?), Lepidocyclina (Nepthrolepidina) sp., Lepidocyclina sp. Possibly a fourth species of Lepidocyclina.
• Bed 3 - Lepidocyclina trinitatis (?) and L. (Nephrolepidina).

Above Bed 3 is another barren sandstone and then a conglomerate with lime cement, carrying Lepidocyclina gigas and marking the base of the Oligocene.

• Wilson et al. (1957).
• Woodring (1960). Poorly defined name. The David Fm, which consists of fossiliferous limestone and shale separated by barren sandstone, has yielded the type material of Lepidocyclina macdonaldi, L. duplicata [L. pustulosa tobleri], Orthophragmina minima [Asterocyclina minima], and Nummulites davidensis [Operculinoides floridensis]. In oral an communication, C.W. Cooke reports that the David Fm contains Oligopygus cf. O. wetherbyi. The David Fm has been referred to the upper Eocene, but, like the Búcaro Fm, may be late middle Eocene or may include late middle Eocene. The fossils from the David include a small species of Velates which has a very eccentric apex similar to that of the much larger V. vokesi.
• Keroher et al. (1966)