Marks (1951) Loc. # 534 (Progreso Fm) (Miocene of Ecuador)

Where: Guayas, Ecuador (2.3° S, 80.4° W: paleocoordinates 3.5° S, 76.3° W)

• coordinate based on nearby landmark

• outcrop-level geographic resolution

When: Progreso Formation, Early/Lower Miocene (23.0 - 16.0 Ma)

• From Progresso Fm, which is of Middle Miocene age, overylies the Subibaja Fm (lower Early Miocene). The thickness of the formation is about 200 ft throughout its outcrop area. It is regionally correlated with the Variegated, Upper Zorritos, Cardalitos (Peru) and Onzole and Borb√≥n (Ecuador) formations.

• bed-level stratigraphic resolution

Environment/lithology: coastal; poorly lithified, pebbly, tuffaceous, green, argillaceous, silty, conglomeratic, calcareous sandstone

• Shallow marine and brackish water with typical tropical assemblage.
• Clay, silty, green sandstone; soft, silty, and silty shale, with local accumulations of bentonite, bentonitic shale, tuff, pebbly sandstone, oyster-rich sandstone with duriable calcareous cement, and fine conglomerate.

Size class: macrofossils

Reposited in the PRI

• Fossil material derived from the International Ecuadorian Petroleum Company (subsidiary of Standard Oil Co.) and was collected by the author (then employed by oil company) during field exploration and drilling operations. All type and voucher material reposited in PRI collections.

Primary reference: J. G. Marks. 1951. Miocene stratigraphy and paleontology of Southwestern Ecuador. Bulletins of American Paleontology 33(139):1-448 [A. Miller/A. Hendy]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 61063: authorized by Austin Hendy, entered by Austin Hendy on 29.05.2006

Creative Commons license: CC BY (attribution)

Taxonomic list

• Exhaustive for gastropoda and bivalvia.
 Pectinida - Pectinoidae
"Pecten woodringi" = Argopecten woodringi
"Pecten woodringi" = Argopecten woodringi Spieker 1922 calico scallop
 Cardiida - Veneridae
"Chione aff. latilirata" = Lirophora (Lirophora) latilirata, "Dosinia delicatissima" = Dosinia (Dosinia) delicatissima
"Chione aff. latilirata" = Lirophora (Lirophora) latilirata Conrad 1841 venus clam
"Dosinia delicatissima" = Dosinia (Dosinia) delicatissima Brown and Pilsbry 1913 venus clam
 Sorbeoconcha - Turritellidae
"Turritella infracarinata" = Turritella (Turritella) infracarinata
"Turritella infracarinata" = Turritella (Turritella) infracarinata Grzybowski 1899 turret shell