Also known as Loc. 19
Where: Baja California Sur, Mexico (26.2° N, 112.3° W: paleocoordinates 24.9° N, 103.9° W)
• coordinate based on nearby landmark
• outcrop-level geographic resolution
When: San Gregorio Formation, Chattian (28.1 - 23.0 Ma)
• The San Gregorio Formation lies unconformably below the upper Ysidro sandstone and appears to be no more than 400 ft thick. Because of its similarity to the Monterey Formation of California Darton (1921) tentatively correlated the beds and named them the "Monterey beds". Limited evidence points to an Oligocene age, although the formation is tentatively assigned an Oligocene to early Miocene age based on macrofossils and diatoms.
• bed-level stratigraphic resolution
Environment/lithology: marine; brown, argillaceous shale
Size class: macrofossils
Collection methods: quarrying,
• Collected by Darton (1921), studied and determined by J. Gardner. No known repository.
Primary reference: C. H. Beal. 1948. Reconnaissance of the geology and oil possibilities of Baja California, Mexico. Geological Society of America Memoir 31 [A. Miller/A. Hendy/A. Hendy]more details
Purpose of describing collection: biostratigraphic analysis
PaleoDB collection 43805: authorized by Austin Hendy, entered by Austin Hendy on 26.08.2004, edited by Mark Uhen
Creative Commons license: CC BY (attribution)
Taxonomic list
Mammalia | |
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Echinoidea | |
"Scutella andersoni" = Vaquerosella andersoni
"Scutella andersoni" = Vaquerosella andersoni Clark and Twitchell 1915 sand dollar | |
Gastropoda | |
Turritella cf. margaritana Nomland 1917 turret shell | |
Vermetus sp. Daudin 1800 worm shell | |
Chrysodomus sp. Swainson 1840 true whelk | |
Bivalvia | |
"Leda sp." = Nuculana
"Leda sp." = Nuculana Link 1807 pointed nut clam | |
"Crassatellites (Crassinella) sp." = Crassinella
"Crassatellites (Crassinella) sp." = Crassinella Guppy 1874 clam | |
Solen sp. Linnaeus 1758 clam | |
Chione sp. von Mühlfield 1811 venus clam | |
Cardium sp. Linnaeus 1758 cockle | |
Macoma sp. Leach 1819 tellin clam | |
"Arca cf. mediaimpressa" = Anadara (Anadara) mediaimpressa
"Arca cf. mediaimpressa" = Anadara (Anadara) mediaimpressa Clark 1918 ark misspelled as "Arca cf. medioimpressa"
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"Pecten cf. crassicardo" = Lyropecten crassicardo
"Pecten cf. crassicardo" = Lyropecten crassicardo Conrad 1856 scallop |