"Now the United States of America, in consideration of the premises and in conformity with the act of Congress aforesaid, does give and grant unto unto the said Pueblo of Pecos, in the county of San Miguel aforesaid, and to the successors and assigns of the said Pueblo of Pecos, the tract of land above described and embraced in said survey but with the stipulation and as expressed in said act of Congress "That this act of confirmation shall only be construed as a relinquishment of all title and claim of the United States to any of said lands and shall not affect any adverse valid rights, should such exist. ...""