From 1828 to 1832, he was an efficient member of the Territorial Legislature, where he introduced a system of township and county names, formed on the basis of the aboriginal vocabulary, and also procured the incorporation of a historical society, and, besides managing the finances, as chairman of an appropriate committee, he introduced and secured the passage of several laws respecting the treatment of the native tribes.
In 1828, the Navy Department offered him a prominent situation in the scientific corps of the United States Exploring Expedition to the South Seas.

This was urged in several letters written to him at St.Mary's, by Mr.Reynolds, with the approbation of Mr.Southard, then Secretary of the Navy.

However flattering such an offer was to his ambition, his domestic relations did not permit his acceptance of the place.

He appeared to occupy his advanced position on the frontier solely to further the interests of natural history, American geography, and growing questions of philosophic moment.
These particulars will enable the reader to appreciate the advantages with which he commenced and pursued the study of the Indian languages, and American ethnology.

He made a complete lexicon of the Algonquin language, and reduced its grammar to a philosophical system.