Ancient petroglyphs ripped from stone at California rock art site

LOS ANGELES, Nov 20 (Reuters) - Four petroglyphs carved into

volcanic rock more than 3,500 years ago have been hacked out and

stolen by thieves who also damaged other engravings at a

historic site in California, U.S. authorities said on Tuesday.

The petroglyphs in the Volcanic Tablelands east of Yosemite

represented a "pristine example of Great Basin rock art" that

portrayed the daily hunter-gatherer activities that took place

in the area, the Bureau of Land Management said.

"The individuals who did this have destroyed an

irreplaceable part of our national cultural heritage,"

Bernadette Lovato, Bureau of Land Management field office

manager, said in a statement.

"We have increased surveillance of our sites and are working

with other agencies to bring the responsible parties to justice

and to recover the petroglyphs," Lovato said.

It was not immediately clear when the petroglyphs, or rock

engravings, were removed from the site near California's border

with Nevada. A volunteer monitor first spotted the damage on

Oct. 31, bureau spokesman David Christy said.

"This is terrible. This place is on the National Register of

Historic Places," Christy told Reuters. "Among the rock art

community, it's known as one of the outstanding examples of rock

art."

Christy said the thieves would have needed ladders, concrete

cutting saws and power generators to cut out the petroglyphs -

not a fast or easy job.

"This wasn't casual, somebody walking around picking up

arrowheads. This was a serious effort," he said.

No suspects have been identified so far. Christy said the

petroglyphs had not yet surfaced on the black market for stolen

antiquities.

The Volcanic Tablelands are described by the Bureau of Land

Management as a vast volcanic landscape formed more than 700,000

years ago by materials spewing from the Long Valley caldera to

the northwest.

The high-desert site and its volcanic rock outcroppings are

listed in the National Register of Historic Places, protected

under the Archaeological Resources Protection Act and still used

by local Paiute Indians for ceremonies.

"The location of archaeological materials, feature remains

and the rock art clearly portray the activities that occurred at

the site during the last 3,500 years," Greg Haverstock, an

archaeologist for the Bureau of Land Management's field office

in Bishop, California, said in a statement.

The Bureau of Land Management has offered a $1,000 reward

for information leading to the arrest and conviction of the

people responsible for the theft.

According to the Bureau of Land Management, first-time

violators of the Archaeological Resources Protection Act can be

imprisoned up to one year and fined $20,000.

(Reporting by Dan Whitcomb; Editing by Cynthia Johnston and

Peter Cooney)