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fossils suggests the area was once under a shallow bay, with relatively uniform levels of salinity and sand porosity. The shell beds form a conglomerate in a calcerous sandstone matrix; today, this conglomerate is a major component of notable geological features in the Bay Area, including
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The
Tularcitos syncline is a significant geological feature in the southern part of the formation. The high level of deformation, compared to the northern area, suggests that there was significant metamorphic activity, enabling the formation of
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in distinct, parallel layers. The sandstone is unique in its relative coarseness and light coloration. Some areas also include a pebble conglomerate.
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as opposed to open grasslands or forest, though many different vegetation types have been documented occurring on the
Briones Formation.
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The presence of rocks of the
Briones formation near the surface creates conditions conducive for the development of
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333:"Zeolites in the Miocene Briones Sandstone and related formations of the central Coast Ranges, Calif"
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and high levels of runoff. Today, the land is used primarily for grazing.
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Google Books: "Names and
Definitions of the Geologic Units of California"
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The vegetation present in the area is primarily annual grasses and
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List of fossiliferous stratigraphic units in
California
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280:"Fossilworks: Gateway to the Paleobiology Database"
278:Various Contributors to the Paleobiology Database.
143:dating back to the Late/Upper Miocene epoch of the
162:, and S. falcata. The presence of shell beds and
340:Journal of Research of the U.S. Geological Survey
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305:"Geology of the Hayward quadrangle, California"
385:"Official Series Description - BRIONES Series"
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536:Geology of Contra Costa County, California
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331:Murata, K. J.; Whiteley, K. R. (1973).
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150:. Common fossils in the area include
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561:California geologic formation stubs
174:The base of the formation includes
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541:Geologic formations of California
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556:Miocene Series of North America
420:This article about a specific
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484:. You can help Knowledge by
473:This article related to the
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389:soilseries.sc.egov.usda.gov
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244:Paleontology in California
234:Miocene California geology
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361:"Mission Creek - Geology"
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268:, Issues 825-830, pg 73.
139:The formation preserves
127:It is found in western
107:Late/Upper Miocene epoch
118:San Francisco Bay Area
427:in California is a
129:Contra Costa County
64:Contra Costa County
49:San Pablo Formation
25:Stratigraphic range
531:Miocene California
110:geologic formation
39:Geologic formation
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365:www.msnucleus.org
226:California portal
103:Briones Formation
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199:permeability
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169:Mission Peak
160:Clinocardium
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85:Type section
285:17 December
525:Categories
394:2022-10-22
370:2022-10-16
314:2022-10-22
250:References
188:laumontite
122:California
69:California
551:Tortonian
546:Messinian
425:formation
206:Chaparral
180:siltstone
176:sandstone
90:Named for
45:Underlies
212:See also
114:East Bay
55:Location
475:Neogene
164:mollusk
152:Spisula
145:Neogene
141:fossils
135:Geology
112:of the
75:Country
29:Miocene
478:period
148:period
60:Region
480:is a
336:(PDF)
195:forbs
105:is a
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429:stub
287:2021
178:and
101:The
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