http://sidneyrigdon.com/criddle/rigdon1.htm#22
Samuel F. Whitney:
“I heard Sidney Rigdon preach… in 1827 or ’28. He said how desirable it would be to know who built the forts and mounds … Soon it would all be revealed.”
John Rudolph:
“For two years before The Book of Mormon appeared Rigdon’s sermons were full of declarations and prophecies that the age of miracles would be restored, and more complete revelations, than those in the Bible, would be given.”
Reuben Harmon:
“I was personally acquainted with Rigdon….I have heard [him] several times say in his sermons that before long the Indian mounds and forts about there would all be explained.”
Adamson Bentley, Rigdon’s brother-in-law, wrote to Walter Scott on Jan 22, 1841:
“I know that Sidney Rigdon told me that there was a book coming out, the manuscript of which had been found engraved on gold plates, as much as two years before the Mormon Book made its appearance, or had been heard of by me.”