I can't find the actual book online, Early Settlers of Weld, E.J. Foster, but a transcription online states, "Amaziah Reed and Lemuel Jackson also came in 1803; they were from Greene, and were both ministers of the Baptist church. They bought land and made clearings, and in 1804 brought their families. Mr. Jackson came from Middlesex, Mass., to Greene in 1798, then from the latter place to No. 5 in 1803; he began his farm near Mr. Parkhurst's, where Jacob Holman now lives. His wife was Mindwell Ward of Augusta. He moved west in 1818; he was called in his time a smart preacher, though he could neither read nor write; he commenced to hold meetings in 1804 and formed the Baptist church in 1809 with about fifty members, most of whom were on the west side of the pond." Rootsweb transcription also gives some info on birth and land records.
I found Lemuel in the 1800 Greene Kennebec Maine census living next to Amaziah Reed. "United States Census, 1800," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:XHR8-ZMH : accessed 11 February 2023), Lemuel Jackson, Greene, Kennebec, Maine, United States; citing p. 249, NARA microfilm publication M32, (Washington D.C.: National Archives and Records Administration, n.d.), roll 7; FHL microfilm 218,677.