Complex sentence: Senator McCumber was sent to meet with the Pembina Band of Chippewa Indians and during the first meeting, when he was not present, his agent Waugh offered $0.10 per acre.
Split into simpler sentences: Senator McCumber was sent to meet with the Pembina Band of Chippewa Indians. During the first meeting, when the senator was not present, his agent Waugh offered $0.10 per acre.