Individual Details

Pelatiah and his son Sylvester remained in Ohio when the remainder of the family moved to Illinois. He is most often seen in databases as "Pellathin" but I believe it is much more likely he was named for his grandfather, Pelatiah Hall.

1860 Census. Norwich Twp, Franklin Co, Ohio, Hh 596
Pelitia Avery, age 50, Produce Jobber, b. PA
Eda, 45.
John McDonald, 30
John Johnson 18
Mary Twigg 17
Samuel Twigg 11

Ohio County & Family Histories, 1780-1970 [Genealogy.com]: HISTORY OF FRANKLIN, PICKAWAY COUNTIES, OHIO.
p.496 P. S. Avery was one of the first officers of the Norwich Lodge, #385, Independent Order of Odd Fellows, chartered and instituted on 25 Jun 1867.
p.153 Sylvester Avery [son of P. S.] was a Private in Company I, of the 133rd Regt, National Guard of Ohio [Civil War]. The Regiment of 917 men was mustered out 6 May 1864 and ordered to West Virginia to destroy the Richmond & Petersburg Railroad. They were mustered out 20 Aug 1864 at Camp Chase.

1870 Census. Norwich, Franklin, Ohio, P.O. Columbus, Hh 258
Pelatiah Avery, 60, Retired Farmer, b. PA
Eda, 56., b. Ohio

Ohio County Death Records:
Eda Avery died 19 Sep 1873, Norwich Twp, Franklin Co, Ohio. She was 59 and married; born in Ohio. Her parents were Benjamin and Elizabeth Britton.

Ohio County Marriage, Franklin Co
P. S. Avery license to marry Mary Jane Zell, 10 March 1874. They were married on March 15th by J. Romick, Elder of the UB Church

NOT this man - it's his grandson
Ohio County Marriages, Franklin Co
21 Mar 1879 license issued to Peletiah S. Avery to Mary Lucinda Sands. They were married on the 23rd of March by A. M. A. Forshee

1880 Census: Norwich, Franklin Co Ohio. P. S. Avery, Farming. age 70, b. PA. Mary J. Avery, wife age 46, b. Ohio, her father b. NY, mother b. PA. (Note: the information for the wife seems to be that of Mary Jane, not Lucinda) John Cain, age 24, was living with them probably as a hired hand.
In Washington, Franklin Co OH was found Martha Avery, widow, age 39, born Ohio and her son Sylvester, age 15. I would think this is perhaps the widow of Pellatin's son Sylvester and a grandson.
Two doors from Martha Avery was Pelvin Avery, age 20 and his wife Lucinda, 20. I believe this explains the problem. Pelatiah, b. 1810 was never married to Mary Lucinda Sands - this was a younger man - his grandson

Sylvester & Martha also had a daughter Edith, born 1860 in Hillard, Franklin Co. Edith's marriage to her second husband, William Dominy, states her mother's maiden name as Kidwell. Edith was first married to Riley Houchard.

In 1890, Martha was in the Ohio Census of Union Veterans and Widows of the Civil War
She was in Washington Twp, Franklin Co, OH
Martha E. Avery, widow of Sylvester Avery who served as a Private in the 113th Infantry. He enlisted 20 Aug 1862, discharged 20 Aug 1864 (probably date of death). Served 3 years, 2 months, and 5 days

1900 Census. Dublin, Washington Twp, Franklin, OH, Hh 150
Edith W. Houchard, b. Oct 1860, age 39, a widow, 3 children, b. OH, farmer
Otto F., son, b. Feb 1881, age 19
Orville C., son, b. Jun 1885, 14
Amos R., son, b. Aug 1893, 6
Hh 151
Martha Avery, b. Aug 1840, age 59, widow - she had 5 children, 3 are living

1900 Census. Hillard Village, Norwich Twp, Franklin Co OH, Hh 75
Levi Helser, b. Aug 1836, age 63, married 4 years, Captialist
Lucinda M., wife, b. Feb 1859, 41, has had 3 children - 1 is living
Oscar Avery, Stepson, b. Jul 1880, age 19, Salesman, Elec. Supply

Ohio County Marriages, Franklin Co
10 Mar 1904. Oscar Avery, license to marry Sue B. Young. Osacr was 24, born on 8 July, in Hillard, Ohio, and was a clerk. His father was P. S. Avery; his mother's maiden name L. M. Sands. Sue B. Young was also 24, born 23 Sep in Boston, Mass. Her father was David Young; her mother Ella Jane Cooper. They were married that same day by James S. Ricketts, Minister of the Gospel.

Mary L. (Lucinda) Helser, died Franklin Co, OH, 11 Nov 1941.

Birth	1810	Lycoming County, Pennsylvania
Death	1891	Franklin County, Ohio

Father	DANIEL AVERY (1768 - 1848)
Mother	SARAH "Sally" Sargent (1772 - 1840)
Sibling	Stephen AVERY (1796 - 1849)
Sibling	Daniel AVERY Jr. (1797 - 1851)
Sibling	Mary "Polly" AVERY (1799 - 1850)
Sibling	Chancy AVERY (1801 - )
Sibling	WILLIAM AVERY (1803 - 1867)
Sibling	Anna "Nancy" AVERY (1804 - 1870)
Sibling	Elizabeth "Betsy" AVERY (1807 - 1883)
Sibling	Mariah Avery (1813 - 1844)
Sibling	Sarah "Sally" AVERY (1817 - 1849)