ORWIN SPRINGS, Mont. — Alex White Plume watched, frustrated, as 20 buffalo trotted south up Paradise Valley, back into the safe haven of Yellowstone National Park. A hundred buffalo or more grazed farther inside the park, near the border but unwilling to cross it.

No buffalo would be shot on this bitterly cold morning last week. The Oglala Sioux tribe would receive no more meat.

"I think morale here is running low," White Plume said, as the sun broke over the Bear Tooth Mountains, painting the snowcapped 11,000-foot summit of Electric Peak with a pink glow. The buffalo were black specks now, moving slowly over brown foothills west of the Yellowstone River. White Plume's band of 46 Oglala shivered on a gravel ranch road, stamping their feet and drinking coffee in the frosty dawn, some of them watching the buffalo through binoculars.

"This will be hard on us," said the soft-spoken White Plume.

White Plume's ancestors hunted these valleys for millennia, but today's hunt and the future of the tribe's buffalo supply depend on decisions made by a species even harder to predict than the buffalo--Washington bureaucrats.

The Indians' desire to rebuild the buffalo-based economy of their heritage must be balanced against cattle ranchers' concerns about a contagious disease. Only this week does there seem to be progress toward a solution.

Bison have trekked these hills since the late Pleistocene era. The river here tumbles out of Yellowstone's high country, then follows the broad Paradise Valley for 60 miles, north to Livingston, Mont., and beyond. It is one of four major valleys that drain this side of Yellowstone National Park. Once they were lush byways for buffalo, elk and other game.

But today, the Yellowstone River is more likely to attract fly-fishermen. The valley, still spectacular, has been subdivided into ranches, resorts and homes for movie stars.

This was the Oglala's first hunt here in more than 110 years. When 60 million buffalo roamed North America, the Oglala and other Lakota Sioux tribes based their entire culture on the natural movement of the herds. The tribes still use buffalo meat for religious ceremonies, powwows and other gatherings. Buffalo skulls serve as altars. Buffalo hearts are buried beneath the tall poles erected for the Sun Dance, the Lakota's most sacred ceremony.