Holmes spent 13 years saving for the $200,000 well his brother installed a year ago. At 40 barrels a day, its haul exceeds the combined output of his 19 other aging pumps. All older than the 64-year-old oilman, they suck at shriveling reservoirs, barely yielding enough to offset their upkeep.

The gamble on a new pump paid off. But Holmes, one of the last of the mom-and-pop oil producers in California's San Joaquin Valley, envisions a time when it becomes one more lifeless reminder of a better day.

"This is the end of an era," Holmes drawls from under a Stetson-shaped hard hat, his booming voice suddenly subdued.

It's a common refrain in Kern County, heard from aging oilmen to young waitresses. And it's a story familiar in Texas, Oklahoma, Louisiana — even in Los Angeles County cities such as Signal Hill and Long Beach.

The rich oil fields here are slowly running dry, affecting not only independent drillers such as Holmes but also the economic future — and identity — of a region that for a century has helped keep California one of the top oil-producing states.

Kern is still California's top oil-producing county, claiming 37,000 of the 43,000 wells statewide. At nearly 200 million barrels in 2002, the area generates three-fourths of California's oil, more than any state but Alaska and Texas and about one-tenth of overall U.S. production.

Some oil companies continue to invest, and state officials predict there are at least 20 years of crude left in 75 active fields. But it's a finite resource.

Plugging parched wells is now a thriving business. In 2002, regulators issued 2,000 permits to drill new wells and 2,500 to abandon old ones, said Randy Adams of the California Division of Oil, Gas and Geothermal Resources. Where pumps once stood, housing developments and strip malls attest to economic diversification.

The Kern County fields have been declining by 3 percent to 5 percent annually since 1985, Adams said. That's not an exceptionally high rate for an old field, according to industry experts. But because producers already are using advanced technology to tap existing pools, the drop is all the more acute.

Last November, Shell Oil Co. announced it will shutter its 72-year-old refinery in Bakersfield. Processing 70,000 barrels of local oil a day, the 400-worker refinery is one of only 13 in the state that produce California's required clean-air gasoline.

The proposed shutdown sparked protests from politicians and consumers, who argued the closure would hike the already-inflated tab California motorists pay for gas. Under that pressure — and facing state and federal investigations — Shell announced in August it will delay the shutdown to allow more time to find a buyer. But the controversy resurrected questions about California's energy stability, as well as the future of a region whose rise and fall has long followed the pulse of the oil pump.

"People don't realize what oil has meant to the communities of the San Joaquin Valley," said Sally Kinney, 52, a waitress whose grandparents moved from Oklahoma during the Great Depression.

"Used to be, everyone you'd meet had ties in some way to oil," Kinney said. "Now, fewer people know the fields. ... There's too many other options than to tie their future to a resource that won't be around forever."

Two hours north of Los Angeles, beyond the strip malls and superstores of Bakersfield — population 267,000 and growing — lies the once-bountiful valley locals christened California's Golden Empire. Tens of thousands of pumps still gnaw at the amber-colored earth, but the imprint of oil's legacy stretches far beyond the fields.

Streets are named Standard, Gulf, Getty and Shell; nearby towns are Oildale and Oil City.

Forty years after gold lured prospectors to the valley in the mid-1800s, a hand-dug pit that gurgled black gold on the western bank of the Kern River ushered in a new era. Forests of wooden derricks and instant communities sprang up along a swath that, according to the Kern County Museum, would produce more wealth from oil than all the west's gold mines.

California by 1903 had become the nation's top oil-producing state, industry experts say.

The area simply can't maintain past levels, according to local and national experts.