cap rock

American  

Or caprock

noun

Geology.

1. a mass of anhydrite, gypsum, or limestone immediately above the salt of a salt dome.

2. an impervious stratum overlying an oil- or gas-bearing structure.

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cap rock British  

noun

1. a layer of rock that overlies a salt dome and consists of limestone, gypsum, etc

2. a layer of relatively impervious rock overlying an oil- or gas-bearing rock

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Etymology

Origin of cap rock

An Americanism dating back to 1865–70

Example Sentences

By 5:30 p.m., our class of five was gathered in the Cap Rock parking lot — one of the lots that stays open at night for stargazers.

From Los Angeles Times

After a reminder to bring water and a rundown of Cap Rock Trail, which is a 0.4-mile loop with a bathroom near the parking lot, Norris led us onto the trail to start planning our shots.

From Los Angeles Times

From there, they drove to Cap Rock in Joshua Tree, where Kaufman doused the coffin with five gallons of high-test gasoline and lit a match.

From Los Angeles Times

Hiking a social trail behind Joshua Tree National Park’s famed Cap Rock, I came across a peculiar sight that, if you know what you’re looking for, actually isn’t so unusual at all: a crude cross made of dark stones below a scribble of orange graffiti.

From Los Angeles Times

According to Kaufman and several rangers, the body was cremated on a median bordering the Cap Rock parking lot.

From Los Angeles Times