The information you gathered is off the mark. Every census says she was b NE.
1880 Cherokee Co KS CARSON Mercy 40 IA NY NY; wd/div BULLIS, George 11 IA; son FENTON Charles 7IA; son Etta 3 NE; dau CARSON, Temperance 2/12 KS; March; dau
1885 Garfield Co NE CARSON, Mercy 44 NY RI PA BULLIS, George 21 IA FENTON Charles 16 IA Etta 8 NE NY NY CARSON, Edith 5 KS IL NY [Temperance?]
Etta and Clark were m. c 1893.Do you still need the 1900 census? Somewhere along the line they were divorced. Son, Carl Emry DAVENPORT b 5-20-1894 Omaha; d 3-20-1973 Berkeley WV; parents Clark W DAVENPORT/Etta FENTON familysearch.org for death cert.