Water, wind, and calcite erosion in per-volcanic sandstone formation.
Slightly acidic rainwater seeps into the sandstone during winter rains and dissolves some of the calcite. Warm and dry days cause the moisture to pull the dissolved calcium back out of the rock, causing holes and caves to form.
Watch for peregrine falcons and other birds of prey nesting high up in the Castle Rock caves.
The upper trails are closed Feb-July to avoid disturbing the nesting birds.

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Wall Point and Barbecue Terrace Road Loop

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Twin Ponds – Old Borges Ranch loop from Walnut Creek

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Details

Informations

Elevation 100 m

Weather

Tuesday 24 March

28°C

9°C

0 %

Additional weather tips

Max wind speed: 14.0 km/h

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Take Me There

Location: Contra Costa County, California, United States

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Sandstone caves in Castle Rock formations

#1.

Diablo Foothills Regional Park loop

#2.

Wall Point and Barbecue Terrace Road Loop

#3.

Twin Ponds – Old Borges Ranch loop from Walnut Creek

Other Popular Places to Check Out

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