The syntax of books written 150+ years ago is very different than in modern writing and it can sometimes be hard to follow. Or maybe it's just Cooper's writing style. Mark Twain sure liked to point out what he considered the literary mistakes of Cooper and seemed to enjoy poking fun at him.
I collect books, especially old ones and have become used to the old style of writing so it doesn't bother me. I enjoyed all five novels in the Leatherstocking series despite Mark Twain's criticisms.