At dusk, the Whitehorse clan filed inside a tepee to spend the night chanting, drumming and eating hallucinogenic peyote. At midmorning, the Navajos filed out just as the many Mormon residents of this southeastern Utah county were pulling up to the tidy brick churches that poke spires higher than any tepee poles into the horizons of San Juan County.

The Navajo Indians and the white, predominantly Mormon residents of this county say they pray for each other in these services and ceremonies, but that hasn't eased the cultural clash that may break this county in two.Longstanding complaints of racism and governmental inequities have turned the county into a tempest of lawsuits, federal investigations and even a United Nations inquiry. Now, they have prompted an attempt to officially split the county.

The county has hired the University of Utah to research the complex particulars of dividing and has held public meetings for the past year and a half to study the issue.

Since the Mormons first trundled their wagons into this southeastern corner of Utah in 1880 and encountered a dark-skinned people they believed to be descendants of an ancient tribe, the two cultures have collided. Their differences have only deepened in the decades they have been uncomfortably bound together by county boundaries that take in 2,000 square miles of the Navajo Nation reservation.

"It's obvious we can't work together; there is racism at work here," said San Juan County Commissioner Mark Maryboy, the only Navajo elected official in the county, where 53 percent of the residents are Navajo. Maryboy was elected in 1984 after the U.S. Justice Department forced the county to create new districts, one of which had a Navajo majority.

Seventy-five percent of the county's Navajo residents live on the reservation land in the south of the county where there are a couple of rag-tag settlements of government tract houses. Some backyards sport the traditional round earthen hogan dwellings. Fancy pickups and satellite dishes shine incongruously in the yards of others, where well-paid oil field workers live.

Commercial districts in these towns are mainly limited to meager strings of tiny cafes, gas stations and video stores.

About 60 percent of the Navajos still live without electricity or running water. The tribe says that half don't have jobs. More than half don't have high school diplomas. Almost 90 percent receive some kind of public assistance.

Maryboy has long charged that the county has systematically shortchanged the reservation by failing to spend enough money on such services as roads, schools and libraries. A 1989 audit by Arthur Young International upheld that view. It concluded that the reservation brought in more revenues to the county than it received in services, although some commissioners have challenged the audit as ill-conceived.

North of the reservation line lie the tidy, green-lawned, wide-street towns of Blanding and Monticello, home to the descendants of the Mormons who settled here more than 100 years ago. The towns boast two golf courses, a community college, a recreation and cultural center, a museum and some brand new churches and schools. Espresso shops have popped up among the Indian souvenir stores and fast food restaurants.

San Juan County Commissioner Bill Redd stood in front of the old stone courthouse in Monticello and philosophized about why the Mormons and Navajos had such a hard time coexisting.

"When you've been nurtured in one culture it's hard to understand the other," Redd said. "When you get to some issues, you have an impasse in understanding."

He gave an example: The Navajos came to the county during the Persian Gulf War asking for $20,000 to pay for a medicine man ceremony for Navajo soldiers. They argued that the county should pay for this because the county pays to pave roads to Mormon churches.

Murky laws that apply to counties that take in sovereign territories give rise to other county headaches. If the county builds something on the reservation, the structure could become tribal property. County deputies don't have clear authority on the reservation. Summonses for jury duty can be ignored. The county doesn't get reimbursed for ambulances and fire trucks and has to provide services like a health clinic because federal Indian agencies and the Navajo tribe have failed to do so.

Despite the acrimony, it seems that an actual split of the county is unlikely.