scholarly journals Middle Eocene brackish-marine mollusks from the Matilija Sandstone at Matilija Hot Springs, Ventura County, southern California

1999 ◽  
Vol 480 ◽  
pp. 1-29
Author(s):  
Richard L. Squires
Keyword(s):  
Southern California ◽  
Hot Springs ◽  
Middle Eocene ◽  
Marine Mollusks ◽  
Ventura County

Review of the bivalve genus Plicatula from Cretaceous and lower Cenozoic strata of California and Baja California

1997 ◽  
Vol 71 (2) ◽  
pp. 287-298 ◽  
Author(s):  
Richard L. Squires ◽  
Louella R. Saul
Keyword(s):  
New Species ◽  
Los Angeles ◽  
Lower Cretaceous ◽  
Southern California ◽  
Upper Cretaceous ◽  
Baja California ◽  
Middle Eocene ◽  
Baja California Sur ◽  
Northern California ◽  
Three New Species

The Cretaceous and early Cenozoic species of the shallow-marine, warm-water bivalve Plicatula from California (United States) and Baja California (Mexico) are reviewed, and three new species are named. All of these species are representatives of Plicatula and not of the closely related taxon Harpax, which is associated with high-latitude and cool-water regions. The earliestknown Cretaceous species of Plicatula from the study area is P. variata Gabb, 1864, from Lower Cretaceous (Hauterivian Stage) strata in northern California, and our studies show it to be conspecific with Plicatula onoensis Anderson, 1958.Plicatula allisoni new species is from Lower Cretaceous (Albian Stage) strata in Baja California, Mexico. Plicatula modjeskaensis new species is from Upper Cretaceous (Turonian Stage) strata in the Santa Ana Mountains, southern California. A possible new species from the same strata is also mentioned. A poorly preserved specimen of Plicatula? sp. is known from Upper Cretaceous (upper Campanian to lower Maastrichtian) strata in northern California.The only Paleocene species of Plicatula from the study area is P. ostreiformis Stanton, 1896, from lower Paleocene strata of Lake County, northern California, and our studies show it to be conspecific with Ostrea buwaldana Dickerson, 1914. The only previously described Eocene species of Plicatula from the study area is P. juncalensis Squires, 1987, from lower middle Eocene (“Capay Stage”) strata of Los Angeles County, southern California. Plicatula surensis new species is from middle lower Eocene (“Capay Stage”) strata in Baja California Sur, Mexico. In addition, there is a Plicatula? sp. from Eocene strata of Baja California Sur, Mexico.Although Plicatula is of uncommon occurrence north of Baja California, its thermophilic trait makes it useful in recognizing periods of warm climate.

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