This looks like your Allie. 1900 census Rusk Co, TX:
Ferguson, Silas M., h, b Oct 1861, 38, Md 14 yrs, b SC, SC, SC
" Nannie, wf, b Aug 1868, 31, M 14 yrs, 7 ch, 7 lvg, b AL, AL, AL
" William, s, b May 1887, 13, b AL
" Samuel, s, b Mar 1890, 10, b AR
" Lizzie, d, b May 1891, 9, b TX
" Maud, d, b Feb 1893, 7, b TX
" Allie, d, b Sep 1894, 5, b TX *******
" Silas, s, b NOv 1896, 3, b TX
" Dallas, s, b Feb 1900, 3/10, b TX
TX Dth Idx 1890-1976 -- http://search.labs.familysearch.org/recordsearch/start.html?..#w=;p=2;c=1320964;t=searchablehttp://search.labs.familysearch.org/recordsearch/start.html?..#w=;p=2;c=1320964;t=searchable -- You can view digitized copy of original record for more details.
Silas Madison Ferguson, b 27 Oct 1861, SC; d 31 Dec 1944, Troup, Smith Co, TX; buried Henrys Chapel Cemetery; wdowed; father William Ferguson, b SC; informant H.D Searcy, residence Troup, TX.
When you look at the above death index, you will also see the son Silas M. Ferguson. His mother is listed as Nancy Johnson. And, for son Dallas Foman Ferguson, his mother is listed as Nancy Ellen Johnson. You can play around with the TX dth idx for other family members, too.
You'll need to do more research to prove this information. But, S.M. looks like your Samuel Madison -- 1880 census Lawrence Co, AL:
Category: Name;Relationship to head of household; Marital Status; Gender; Race; Age; Birthplace; Occupation; Father's Birthplace; Mother's Birthplace.
W. J. M. FURGUSONSelfMMaleW46SCFarmingSCSC
M. E. FURGUSONWifeMFemaleW46SCKeeping HouseSCSC
S. J. FURGUSONSonSMaleW23SCFarmingSCSC
*****S. M. FURGUSONSonSMaleW18SCSCSC
S. E. FURGUSONDauSFemaleW16SCSCSC
T. S. FURGUSONSonSMaleW12SCSCSC
S. L. FURGUSONSonSMaleW10SCSCSC
A. B. FURGUSONSonSMaleW7ALSCSC
M. E FURGUSONDauSFemaleW3ALSCSC
Happy Hunting (^_^)