Since big law firms buy out small law firms almost every day, there seemed to be little reason to take notice last month when Shea & Wilks, a small specialty practice in Phoenix, was acquired by Snell & Wilmer, one of the largest law firms in the western United States.

Except that Shea & Wilks specializes in federal Indian law, and the acquisition is believed to be the first time a major law firm has taken over a small one for the sole purpose of developing its own Native American law practice.

The acquisition is being viewed by many lawyers as an increasing acknowledgment by some of the powerhouses in the legal profession that as the tribes amass greater wealth and influence through casinos and other big-money enterprises, they represent not only a lucrative market for services but a powerful business force to be reckoned with in a manner befitting the law firms' largest establishment clients.

"Indian Country is becoming more sophisticated about who represents them and the big law firms are catching on to the need for Indian law groups," said Keith Harper, a staff attorney for the Native Americans Rights Fund. "I think we're going to see more of these small [Indian law] practices going into big firms."

Increasingly, as casino-rich Indian tribes diversify their investments and gain greater economic power and self-determination, law firms have been looking to add or expand their Indian work in litigation, lobbying and a wide range of other legal services from land claims and gaming regulation to sovereignty issues and environmental law.

Some established firms, such as Dorsey & Whitney and Holland & Knight, have already made a commitment to Indian representation, expanding their stable of lawyers and consultants who specialize in federal Indian law on a piecemeal basis as needed. Some firms have hired Native American attorneys to make themselves even more attractive to tribes seeking legal help. Indeed, Holland & Knight recently added Philip N. Hogen, a Sioux, who was a former member of the National Indian Gaming Commission and a U.S. attorney in South Dakota.

But when Snell & Wilmer, which has 270 lawyers in offices in Phoenix, Tucson, Salt Lake City and Irvine, Calif.--and a list of 6,000 clients that includes such giants as General Motors Corp. and Intel Corp.--looked to expand its Indian law business, it found a ready-made package in Shea & Wilks.

One of the pioneering boutique law firms specializing in federal Indian law, Shea & Wilks was associated in the late 1940s and early 1950s with Felix S. Cohen, a onetime Indian affairs solicitor in the Interior Department who is credited with being the principal drafter of the Indian Reorganization Act of 1934, which protected tribal lands and permitted them to establish self-government.

Shea & Wilks has represented a number of tribes, but most importantly for Snell & Wilmer, its three partners took with them to their new home their biggest client, the Salt River Pima-Maricopa Tribe.

The three lawyers who joined Snell & Wilmer are Philip J. Shea, Richard B. Wilks and William W. Quinn Jr. Shea and Wilks joined the firm that bore their names in 1965 and 1972, respectively, and Quinn, who had been an ethnohistorian for the Bureau of Indian Affairs, joined in 1989.

In terms of economic development, the Salt River tribe is one of the fastest-growing in the nation. Much of the expansion has been generated by revenue from two highly profitable casinos near Phoenix and Scottsdale, Ariz., each of which reportedly grosses hundreds of millions of dollars annually. The tribe, which has only 5,600 members, does not disclose its earnings.

The tribe also owns golf courses, a cement manufacturing company, a commercial solid waste landfill, a telecommunications firm and Miss Karen's, a national frozen yogurt chain.

Quinn, who is chairman of the Arizona Bar Association's Indian Law section, said that the "mutual needs" of Indian tribes and Snell & Wilmer would be fulfilled by Shea & Wilks joining the larger firm.

"The Indians get great representation, with access to some of the best specialists in the country, and Snell & Wilmer gets major new clients," Quinn said. "They [the firm] have made it in that world."

Quinn predicted big law firms will increasingly acquire Indian law specialty firms in order to create their own Indian law practice groups because "it seems logical to get a collection of specialists under one roof." He said Snell & Wilmer also plans to recruit lawyers who are enrolled members of tribes.

Not all Native American boutiques, however, are looking to be acquired. Two such Washington, D.C., law firms--Sonosky, Chambers, Sachse & Endreson and Hobbs, Straus, Dean & Walker--like being on their own.

"The idea of being under the sway of a larger group of managers is not appealing," said Charles A. Hobbs. Reid P. Chambers added, "We like our independence."

Staff writer Judy Sarasohn contributed to this report.

CAPTION: Shea & Wilks partners, from left, William W. Quinn Jr., Philip J. Shea and Richard B. Wilks, join Snell & Wilmer.