Complex sentence: Lyall was Editor of the "British Critic" 1816-17; a Member of the Hackney Phalanx, the high-church equivalent of the Clapham Sect, and became Editor of the "Theological Library" (1832--46).
Split into simpler sentences: Lyall was editor of the "British Critic" 1816-17 and associated with the Hackney Phalanx, the high-church group. He became editor of the "Theological Library" (1832--46).