Father John Smith Informed us in his letter of some remarkable Signs that lately appeared among the Saints viz on the 14th of June 1840. On Sunday five <[-]> men members of the Church saw two men ride across the Missisippi River from Montrose to Nauvoo. One man was on a white horse & the other on a bay or red horse. The waters parted under their feet & fire flew when their tails moved & they observed the clothing of the men. A few month previous to this a man was seen walking across the river by several believers & others. The Unbeleivers said Probably a mormon was going across to steal sumthing. This is the effect that Signs have on those that Seek them.
[Wilford Woodruff's Journal: 1833-1898 Typescript, Volumes 1-9, Edited by Scott G. Kenney, Signature Books 1993, http://amzn.to/newmormonstudies]