Dusk comes early for many neighborhoods of this plush oasis as the sun, with startling suddeness, drops behind the back of brooding, 10,831-foot San Jacinto Peak.

The shadows cast by the rugged crest of the mountains to the west make jagged light-and-dark patchwork patterns across the city that typify, graphically, the crazy-quilt division of land ownership here.

For while the rich enjoy the sun and other pleasures, fewer than 200 stoic-faced members of the Agua Caliente band of the Cahuilla tribe watch with satisfaction and count their money: Owning half the land, although, in a scattered checkerboard pattern, they have the dominant, united voice as to where this popular watering spot for the wealthy goes next.

The leasehold has been a way of life here since the 1950s for commercial, industrial and residential user alike. If you want to use the Agua Caliente's land for any purpose, you lease -- there is no option and no hope of converting to ownership, ever.

No one knows -- or will admit knowing -- what the net worth or annual income of the Agua Calientes is today. Palm Springs broker Ben Blank, however, refers questions to a survey made "about five years ago" indicating that every man, woman and child in the tribe at that time had an annual lease income of $350,000.

Income generated from the land is tax free -- and also free from capital gains tax on the rare occasions when a parcel is sold -- and the land itself remains off the tax rolls until it is leased. And, at that point, it is the lessee who pays the real estate tax, not the lessor.

Additionally, while Palm Springs has its own planning and zoning commissions, the Indians controlling half the city don't have to pay a bit of attention to any of the rulings. The band has its own planning commission.

"Legally," broker Blank said, "if the Indians should decide to put up a 10-story ferris wheel in downtown Palm Springs, there isn't a thing the city could do about it."

But despite the obvious opportunities for friction -- out of envy or the almost-total immunity from restrictions and regulations that the Agua Calientes enjoy -- there is little of it in evidence. The Indians, with their wealth, keep a low profile, take pains not to abuse the freedoms they have and are highly respected for their business acumen.

When you sign a lease it is customarily for 65 years, and typical rents range from about $45 a month on a $110,000 tract home to as much as perhaps $160 to $170 a month for a house selling for more than $300,000. There is no guarantee for the holder that the lease will be renewed under any terms.

It is a haunting thought for many Palm Springs developers because 20-year leases were previously the rule, and many of these are coming up for renewal, or whatever, in the next year or two. What, if anything, the individual Indian owners will choose to do then about renewal (and on what terms) is anybody's guess.

"We have no policy on that sort of thing," Ray . Patencio, tribal chairman of the Agua Calientes, says stiffly. "It will be a matter between the individual owner and the lessee. And, of course, there's no precedent at this time."

With a full half of Palm Springs and the developable land around it under individual Indian ownership -- and another 2,000 acres of desert land not in the development pattern under tribal ownership and administration -- the Agua Calientes are clearly in the catbird seat. And no one in memory ever quite "fell into it" the way the rag-tail 40 Indians did who made up the entire band in 1876 when President Ulysses S. Grant signed over to them "San Bernardino Base and Meridian, Township 4 South, Range 4 East, Section 14." It was just one of 119 agreements reached with California's 260 tribes and embodied in 18 treaties.

Little attention was paid to the 31,520 acres of arid and apparently worthless land that the Agua Calientes had been granted.

The curious "checkerboard" split of ownership between fee-simple land and Indian-controlled land in and around Palm Springs has its roots in the original surveying which, traditionally, gridded the land into neat "sections" of 640 acres. The grants to the Indians, a spokesman for the Bureau of Indian Affairs said, could not involve land grants that already had been made to the railroads for their rights-of-way. The decision was made, therefore, to allocate the even-numbered sections to the Indians.

Originally, he said, each member of the band was given an entire section, but as its numbers grew new allocations were drawn up by the tribal council giving each man, woman and child 47 acres.

As Palm Springs was developing in the 1920s, '30s and '40s into the monied playground that it is today, the Agua Calientes were very much on the outside looking in. The government forbade them to execute any lease longer than five years, and developers moving into Palm Springs simply confined themselves to fee-simple land and "checkerboarded" their way around the Agua Caliente's tin shacks and open sewers.

It wasn't until 1940 that a tribal member, Lee Arenas, screwed up his nerve, indignation and meager resources and retained Los Angeles attorney David D. Sallee to pursue the cause of the Agua Calientes -- a legal battle that occupied most of the '40s before the tribe was given full control of the land.

"But even then," Ira Birer, president of the Palm Springs Board of Realtors said, "the Bureau of Indian Affairs still limited them to 20-year leases, and you can't interest too many developers on that sort of a deal. As a result you had this checkerboard arrangement with the developers confining themselves to fee-simple land."

What changed it all, though, was the Interest Equalization Act of 1959, tribal Chairman Patencia said, under which Congress permitted leases up to 95 years, "but 65 years became the rule here."

"And the whole thing was just plain, unadulterated luck benefiting the Agua Calientes," a spokesman for the Bureau of Indian Affairs, who declined to be identified, said. "Here was a band of Indians who didn't even have a history and, all of a sudden, they're awash in money."