But the announcement that dozens of parcels would be auctioned off in the Swell, a largely untouched geologic formation, came as a surprise to environmental groups, who are worried that the administration’s energy strategy is shifting away from its promise to be environmentally sensitive.

“We were very surprised and disappointed to see this turn of events,” said Steve Bloch, legal director for the Southern Utah Wilderness Alliance. “It’s a step backwards. To see a place like the San Rafael Swell be put up on the chopping block makes no sense.”

On Monday, the Utah group, along with several other conservation organizations, filed a formal protest with the bureau, asking that it withdraw 55 of the proposed leases. The groups claimed the bureau had not sufficiently weighed the environmental consequences of opening parts of the Swell for drilling.

Bureau officials say that recent policy changes intended to slow the leasing process now ensure that tracts of land, like those within the Swell, are carefully examined before drilling is allowed. And they have disputed assertions that they are appeasing energy companies, which have been critical of the administration for being too restrictive.

“The B.L.M. is continuing to move towards full implementation of more environmentally responsible approaches to oil and gas development as outlined in our May 2010 leasing reforms,” wrote Celia Boddington, a bureau spokeswoman, in an e-mail. “Nationally, implementation is a work in progress but we are already seeing positive results.”