Maine and the federal government are in another angry argument over the claims of two Indian tribes that they own more than half the state.

Maine's Attorney General, Joseph E. Brennan, claimed yesterday to have discovered an ancient treaty in which the Penobscot Indians surrendered all their lands to the British crown.

That treaty, he said, negates the Penobscots' current claim that the federal government is preparing to endorse in court.

Furthermore, Brennan accused the Interior Department of sloppy if not deliberately misleading scholarship and called on its lawyers to reconsider their support of the Penobscot claims.

Interior quickly shot back a counter-claim: That old treaty involved only four Indians who surrendered their small tracts in exchange for British protection; it doesn't affect a significant portion of the Penobscots' aboriginal territory.

Maine and the two tribes - the Penobscots and the Passamaquaddies - have been locked in a lawsuit for four years over the contention that the tribes should be compensated for some 12.5 million acres taken from them in violation of federal law.

The Department of Interior said last week that the Indians' claims to up to 10.5 million acres are valid and that the United States is obligated to assert them in federal court.

Brennan said the Passamaquoddy claims are unaffected by the rediscovered treaty.But the Penobscot claims amount to about three-fourths of the two tribes' total, he said.

The Indians contend that their lands were taken by the state in disregard of the Indian Non-Intercourse Act of 1790. That statute prohibited the taking of any Indian lands under any circumstances without the approval of Congress.

The Indians estimate that value of the land in the billions and have demanded $300 million compensation. In addition, they have said they want some lands returned to them as a reservation. That, in turn, has cast a shadow over land titles of present owners; some 350,000 non-Indians live on the dispute lands. the legal dispute has prevented many Maine municipalities from issuing bonds.

Brennan claimed yesterday that a state historian discovered recently a 1760 treaty in which the Pemobscots surrendered their lands to the Massachusetts Bay Province in exchange for the crown's protection. It means, he contended in a telephone interview, that the Indians had given up their territory before the 1790 law was passed.

The federal government should reconsider its support of the Indians' claims, he said: "This raises a big question about the objectivity and accuracy of their recommendations."

Interior Solicitor H. Gregory Austin said the document was not a treaty after all but was "merely a submission of four Penobscot Indians who signed only for themselves and their families." The document "had no bearing on the merits of the claim," Austin declared.

Brennan could not be reached for comment on Austin's reply.