Majestic mountains, footloose elk and an ancient volcanic crater are serving as lobbyists in a campaign to persuade Congress to buy a 95,000-acre ranch in northern New Mexico.

Three influential Republican members of Congress got a firsthand look at the Baca Ranch on Monday, clearly impressed by the majesty of its pristine meadows and fir-covered mountains.Congress and the Clinton administration have teamed up to hammer out a bipartisan deal that would purchase the land and place it under federal authority. Some environmental groups have criticized a congressional proposal to keep it as a government-owned working ranch, while others have questioned the expense.

The Texas family that owns the ranch has set a deadline for Congress to take some action by December.

"I don't think I've ever been on a ranch that is as beautiful as this and is as unique as this," said Rep. Jim Hansen, R-Utah, chairman of the House subcommittee on national parks and public lands.

Hansen and Rep. Ralph Regula, R-Ohio, joined New Mexico Republican Rep. Bill Redmond on a helicopter tour of the ranch, which is about 60 miles northwest of Santa Fe and is surrounded by the Santa Fe National Forest.

Hansen said he thought most Americans would find the land very desirable, but he and Regula agreed it would not be an easy deal to push through Congress.

An appraisal is under way to determine the fair market value of the land, which some expect to be $100 million or more. The land was valued at $37 million to $55 million in 1980.

The ranch features six valleys and mountains up to 11,000 feet. It also contains much of an ancient volcanic crater known as the Valles Caldera, which is 15 miles across at its widest point.

Redmond described the property as the "Grand Canyon of northern New Mexico."

Under a proposal by Sen. Pete Domenici, R-N.M., the land would operate as a working ranch rather than having it managed directly by the U.S. Forest Service or another government agency.

His proposal would establish a trust and have appointed board members - representing people involved with ranching, recreation, wildlife and other fields - run the property.

Regula said Domenici's proposal, though a new approach, should be considered.

However, several environmental groups last week criticized the trustee management plan, saying it was "based on a dangerous philosophy of privatizing public lands."

The National Parks and Conservation Association, Sierra Club and Audubon Society also questioned Domenici's proposal for having the property run as a potentially self-sufficient ranch through fees from grazing, logging and other activities.