They're in Shipleys of MD, 2002:
Nathan SHIPLEY (24 Apr. 1831 - 22 July 1886, of Nathan, Benj., Richard 3, 2, Adam, 1) m. 4 Mar. 1858, Mary Jane LEMMON.
They had Mary/Maria, 1862
Nettie Irene (1868 - 12 Dec 1912) &
Susie, who dy.
Howard County was not formed until 1851, so Mary would have been born in Anne Arundel, not Howard County.
FamilySearch.org,Howard District, Anne Arundel Co., MD, 1850, LEMMON
David, 48; Mary E., 35
Wm. A., 19; Sarah E., 17; David H., 15; James, 13; Mary, 11; Martha A., 9; Emma W., 7; John R., 5; Rose A., 3; Margaret, 6 mo.
FISHER, Sarah, 77; CAUGHEY, John, 35.
All were b. MD except David LEMMON, 48, & John CAUGHEY, 35, both b. Ireland.
--Mary's middle initial is transcribed I, but check the handwriting.It is all above the line but could be a J.
Lisbon, Howard Co., MD, 1860, LEMMON, David, 64, & Mary E., 54; with Wm., Sarah, James, Martha, John, Rose, Margaret, & Charles.Charles was 8.
At first, I thought that if Mary was 35 & son Wm. was 19in 1850, David might have had a prior marriage, but if Mary was actually 54 in 1860, b. 1806...
Distict 4, Howard Co., MD, 1880, LEMMON
David, 76, he & parents b. Ireland; wf. Mary E., 65
Ch. Martha, 39; Charles, 25
Brother Robert, 74, single, he & parents b. Ireland
Dau. Sarah E. MILLER, wid., 48
Grandch. HOPKINS, Edward, 9; Ann, 5(all b. MD except David & his brother).
--We're back to Mary being b. ca. 1815. However, if she had children from 1831 to 1852, a more likely birth year would be 1812.
Death certificate is online for John Russell LEMMON (9 Sep. 1857 [?], Cooksville, MD - 19 Nov. 1927, Parkersburg, Wood, WV), bu. Mt. Olivet, wid/o Leura Belle FROST,
son of David H. LEMMON & Mary WARFIELD.Informant Pansy WILLEY.
(That verifies the maiden name of the wife of David LEMMON.)