On p. 14 of Jerald and Sandra Tanner's Distorted View of Mormonism: A Response to Mormonism—Shadow or Realty? the author (long believed to be D. Michael Quinn) wrote:
The failure to cite well-known evidence that challenges their conclusions occurs repeatedly in the Tanners' analysis of the seven-volume History of the Church. For example, it is implied (pages 134-35) that the prophecy of Joseph Smith about the Mormons moving to the Rocky Mountains (HC 5:85) was a falsification added to the history after the Mormons were actually in the Great Basin. However, in 1964 (eight years before this edition of Shadow-Reality) Stanley B. Kimball published a bibliography of sources for the Nauvoo history of Mormonism (of which the Tanners should have been aware) where he noted that the Oliver H. Olney Papers (written in 1842-43) at Yale University, "recorded the early plans of Joseph Smith to move west. . . .” [7] If the Tanners did not trust that description, they or their widely scattered friends could have read the versified, anti-Mormon manuscript by Olney, dated July 2, 1842:
As a company is now a forming / In to the wilderness to go / As far west as the Rocky mountains. . . . If this was not the secret whispering / Amongst certain ones of the Church of L.D.S. / And could be easily proven If man could speak. [8]
Notes for the Above:
7 Stanley B. Kimball, Sources of Mormon History in Illinois, 1839-48: An Annotated Catalog of the Microfilm Collection at Southern Illinois University (Carbondale-Edwardsville, Ill., 1964), 24. In the expanded edition published in 1966, this entry was on page 25.
8 Oliver H. Olney Papers, Western Americana, Beinecke Rare Book and Manuscript Library, Yale University, New Haven, Conn.
In response, the Tanners wrote that:
Dr. Clandestine seems to feel that the Olney manuscript sheds new light on the Rocky Mountain Prophecy. Actually, we read this manuscript before we published the 1972 edition of Mormonism—Shadow or Realty? And even cited a reference to plural marriage in our book Joseph Smith and Polygamy, page 7. It was, in fact, partly because of Olney’s manuscript that we said that there “is some evidence that Joseph Smith considered going west to build his kingdom . . . “ (Mormonism—Shadow or Reality? p. 135). In his zeal to prove that we suppressed evidence, Dr. Clandestine seems to have completely overlooked this statement in our book.
In any case, while Olney does indicate that the Mormons were looking west, he says nothing about a prophecy given by Joseph Smith. The reader will notice that Dr. Clandestine says that “Olney recorded the rumors about the move west in July, and someone else recorded the prophecy in August.” He is unable, however, to tell us just who this “someone else” might be, and has to admit that “the exact source for the account of Joseph Smith’s prophecy of August 6, 1842 is not clear.” (Jerald Tanner and Sandra Tanner, Answering Dr. Clandestine: A Response to the Anonymous LDS Historian [rev ed.; Salt Lake City: Utah Lighthouse Ministry, 1978], 30)
Since the Tanners wrote this, Olney's journals have become available en toto. See Oliver H. Olney's 1842 Journal Entries on the Saints Then-Future Move to the Rocky Mountains
On Joseph Smith's Prophecies in general, see
Resources on Joseph Smith's Prophecies