I recently found the folowing information in the St. Mary's of the Barrens Catholic Church Records for Perry County, Missouri:

FERGUSON, Augustine
born 14 Feb 1824
baptized 7 Jul 1828 (at Fergusons')
father Daniel
mother Rebecca Pierce

FERGUSON, Daniel
born 29 Jan 1826
baptized 7 Jul 1828 (at Fergusons')
father Daniel
mother Rebecca Pierce

FERGUSON, Rebecca
born 25 Dec 1821
baptized 7 Jul 1828 (at Fergusons')
father Daniel
mother Rebecca Pierce

FERGUSON, Lucy
born 12 Mar 1828
baptized 7 Jul 1828 (at Fergusons')
father Daniel
mother Rebecca Pierce

This is a different Daniel Ferguson in Perry County than the one married to Mary Winfield. I believe these Daniels were cousins since both came from the Washington/Nelson County area of Kentucky.

The 1830 Perry Co, MO census contains this Daniel Ferguson family as well as the widowed Mary Winfield Ferguson family.

Rebecca purchased land in St Francois Co, MO in 1837 and is in that county for the 1840 census.

Rebecca Pierce Ferguson apparently re-married a Mr. Wines and is in Jackson, Ste. Genvieve, Mo for the 1850 census. It shows that she was born in 1803 Vermont. Austin lists his mother as being from VT in the 1900 Ste. Genevieve, Ste. Genevieve Co, MO census.

Austin and his younger brother Daniel are living together in Jacksoon, Ste. Genevieve, Mo for the 1870 census.

I believe the whole family originally came from MD or VA. A Daniel Ferguson married Charity Austin (b. Jun 1761) 14 Jun 1785 in Middleton, Frederick, MD. Daniel Ferguson is living 2 houses down from a James Austin and next door to a William Yates in the 1790 Washington Co, MD census. This Daniel moved to Washington Co, KY and died before 1798. Charity re-married an Ignatius Yates 12 Oct 1798 in Washington Co, KY and then moved to Perry Co, MO. Charity died in Perry Co on 3 Sep 1823. The Yates and Fergusons (as well as their Winfield, Vessels, Layton, Webb, Powers, Thompson and Tucker in-laws) were all members of the St Mary's church in Perry Co, MO.