The preaching of 19th century American Presbyterians was more textual and topical than what we understand as expositional preaching today. They would take a verse or snippet of a verse, explain its meaning in its immediate context, and then unpack and apply that meaning to their people from many different angles. Each sermon is more of what we would think of as an in-depth theological study of a particular topic, but they were never merely for theology's sake. Rather, the goal was conversion of the lost, and transformation of the found, through the knowledge of the truth.
One of the early preachers of the American Presbyterian church was Moses Hoge, a student under William Graham and later James Waddel. He became the President of Hampden-Sydney College in 1807, and helped lay the foundation for Union Theological Seminary in Virginia. His sermons were renowned for their eloquence and erudition, and are found here.