In the 1860 PA Census [Westmoreland Co. > Rostraver Twp.] William T. Marshall appears at age 16 in the household of Christena (age 40), Mary (age 13) and Margaret E. (age 11) Marshall. Christena and her apparent three children had been absorbed into the household of her parents, Thomas and Mary Hayden, along with a number of Christena's younger siblings.

Moving back a decade to the 1850 census, Christena is still listed in the household of her parents, but with only Mary (age 2) and Margaret E. (age 1 month). It is not clear why William T. is not listed with the family as a 6-year-old. Christena and her children had been absorbed into the household of her parents after the premature December 1849 death of her husband, Samuel Marshall.

Now, November 2017, I have been established as a strong DNA connection to a descendant of William T. Marshall, enabling me to establish him as a brother to my own ancestor, Mary Ellen Marshall.
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Roll of Company "B", 77th Regiment, Infantry, Pennsylvania Volunteers, p. 61.

Number: 115
Name: MARSHALL, WILLIAM T.
Rank: Private
Age: 20
Joined For Duty and Enrolled:
When: August 18, 1864
Where: Greensburg, Pa.
By Whom: Capt. Coulter
Mustered Into Service:
When: August 18, 1864
Where: Greensburg, Pa.
By Whom: Capt. Coulter
Term of Service: 1 year
Residence: [blank]
Remarks: Discharged June 16, 1865.
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1870 PA Census: Fayette Co. Washington Twp. P.O. Fayette City, p. 527a, lines 32-35
Series M593, roll 1343, dwelling 179, family 186, 27 June 1870

Wm. MARSHAL, age 26, Coal miner, b. Penna.
Allice, age 19, Keeping House, b. Penna.
Jane, age 1; Margaret, age 1/12, b. June
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1880 PA Census: Westmoreland Co. East Huntingdon, ed 91, p. 46, lines 35-42
Series T9, roll 1203, dwelling 314, family 428, 18 June 1880

Wm. MARSHALL, age 30, married, Coal Miner, b. Penna., parents b. Penna.
Alice, age 29, wife, married, Keeping House, cannot write, b. Penna., parents b. Penna.
Eliza J., age 10, daughter, working out, attends school
Marg., age 9, daughter, at home, attends school
Annie, age 5, daughter, at home
Samuel, age 3, son; John W., age 2, son; Laura, age 1/12, b. April, daughter
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Dixmont State Hospital Burial Records
[See http://freepages.genealogy.rootsweb.ancestry.com/
~njm1/dixbeta1.htm]

Grave Number: 628
Name: MARSHALL, WILLIAM
Date of Death: 12-28-1894
Age: 51
Sex: Male
Nativity: Unknown
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Civil War Pension Index Card

Name of Soldier: MARSHALL, WILLIAM T.
Name of Dependent: Widow, MARSHALL, ALICE A.
Service: B-77 Pa. Inf.

Date of Filing: 1890 Aug. 20
Class: Invalid
Application Number: 908,450
Certificate Number: 714,957
State From Which Filed: Pa.

Date of Filing: 1895 June 18
Class: Widow
Application Number: 616,464
Certificate Number: 464,333
State From Which Filed: Pa.

Attorney: John L. Francis
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