A date of birth is given as circa 1797 in unconfirmed information (blue hand-written document of unknown source) collected by Brian Oliver of nzolivers.com (b.1950) on his April 2008 visit to Devon.

This would place William as the eldest of the children. However, his father’s (John) Will of 29th October 1842, listed those sons that emigrated together in a separate paragraph (perhaps they received help with their passage the previous year). The order of their names were: James, William and Samuel. Brian of nzolivers.com says that if one assumes the children are listed in age order, then James is older than William.

Because of this, and without any further information to contary, Brian is guessing William’s date of birth somewhere between 1800 and 1810.

What happened to William? In his father’s (John) Will, one pound was to go to William, the same amount that went to James and Samuel. James and Samuel both emigrated to New Zealand in 1841. Did William emigrate somewhere?
Brian Oliver's ( b.1950 nzolivers.com) father, Maurice Oliver, and Maurice's brother, Bruce Oliver, both believed some of the family went to the United States of America? Can anyone help here?

Sarah Ferguson (nee Churton) list year of birth as ca 1806.

Date and place of baptism from Baptism, Marriage, Burial records online for St Giles in the Heath, Book no. 2 from year 1760, as alerted by Katia and Tim Oliver In an email dated 4 January 2021.
Tim Oliver is a x3 great grandson of James and Ruth Oliver, his grandfather being Ivor James Clark Oliver (1907-1989).
Name: William Oliver
Event Type: Baptism
Event Date: 05 Aug 1810
Event Place: St Giles on the Heath, Devon, England
Sex: Male
Father's Name: John Oliver
Mother's Name: Grace
From Scans of original parish registers from Cornwall [including Devonshire] containing baptisms from 1538 to 1910 published on FamilySearch:
https://familysearch.org/ark:/61903/1:1:QGLV-P5G8
Note: Login to FamilySearch required

Wow! Mystery solved. William did emigrate to the USA.
Name, confirmation born circa 1810, name of wife and names of her family, occupation, emigrated to the USA, from Katia, wife of *Tim Grant Oliver, in an email dated 30 September 2022, where Katia referred to an image of a passenger list:
Passenger Lists, Collector Office, District of New York:
For the Ship Druid that departed Bristol, England and arrived Port of New York on 29 Jun 1840:
Names | Age | Profession | Place of Residence | Intended Place of Residence
Thomas Harris, 63, Farmer. Cornwall, Ohio
Elizabeth Harris, 60, Farmer. Cornwall, Ohio
Hannah Harris, 32, Farmer. Cornwall, Ohio
Thomas Harris, 26, Farmer. Cornwall, Ohio
Oliver Harris, 20, Farmer. Cornwall, Ohio
John Harris, 18, Farmer. Cornwall, Ohio
Maria Harris, 17, Farmer. Cornwall, Ohio
William Oliver, 30, Farmer. Cornwall, Ohio
Sophia Oliver, 29, Farmer. Cornwall, Ohio

*Tim Oliver is a x3 great grandson of James and Ruth Oliver, his grandfather being Ivor James Clark Oliver 1907-1989.

Date and place of marriage, confirmation of wife's maiden name as "Harris", from Katia, wife of Tim Grant Oliver, in the same email dated 30 September 2022, where Katia referred to a marriage record:
First name(s): William
Last name: Oliver
Marriage year: 1837
Marriage date: 21 Jun 1837
Parish: North Petherwin
Place: North Petherwin
Groom's first name(s): William
Groom's last name: OLIVER
Bride's first name(s): Sophia
Bride's last name: HARRIS
County: Cornwall [Was historic county of Devon]
Country: England
Record set: Cornwall Marriages
[North Petherwin is a civil parish and village in the historic county of Devon and the ceremonial county of Cornwall, England, 3.5 miles from Boyton and 7 miles from St. Giles in the Heath].

Place of residence, confirmation of estimated year of birth, from 1850 Free Inhabitants Ohio USA Census enumerated on 7th day of August 1850, for the Monroe Township in the County of Knox Ohio, from Katia, wife of Tim Grant Oliver, in the email dated 30 September 2022:
Name | Age | Sex | Profession | Value of Real Estate | Place of Birth | Intended Place of Residence
William Oliver, 40, Male, Farmer, $3,000, England
Sophia Oliver, 39, Female, --, --, England
Thomas Barrable, 12, Male, --, --, England
Jane Caldwell, 13, Female, --, --, England

William’s Will
Verification that this William is our William, date of birth of "August 3rd 1810", from his Will dated 18th November 1896, and Probate dated 24 March 1904, from Katia, wife of Tim Grant Oliver, in the email dated 30 September 2022. The verification is in the Eight Clause referring to family back in England:
EIGHTH:- All the residue and remainder of my estate real and personal not above divided or bequested I will and I direct to be divided into four shares and
one share thereof distributed to Jennie Carlisle mother of Wm. M. Carlisle
one share to Jennie Rae daughter of my sister Mary Goodman and
Two shares to my sister Ann Walters two daughters Harriet Honey and Mary Grace Parnell equal between them in England.

William Oliver had only two sisters:
- Mary Oliver
- Ann Oliver (married a William Walters already in ‘The Tree’).

William’s sister Ann Walters (nee Oliver) had three daughters; Harriet, Amelia, and Mary Grace. I wonder why daughter Amelia was missed out in the above Will? Perhaps she had died?

Also in the above Will, there are some questions that come out of it:
QUESTION: There no mention of William’s wife, Sophia. Has she already passed away by then?
ANSWER: Sophia had died earlier on 27 November 1885.

QUESTION: No mention of any children?

QUESTION: How is Jennie Carlisle related?
ANSWER: She is the mother of William’s nephew William M Carlisle. Still need to find the connection?

Further examination of Will
In the FIRST article, debts and funeral expenses to be paid
In the SECOND article, nephew William M Carlisle inherits a farm that he currently resides in Monroe Township, Knox County, half interest in stock and tools, and two pictures of himself and Sophia.
In the THIRD article, Jennie Carlisle, mother of William M Carlisle, two promissory notes, each worth 200 dollars, plus interest, from her husband Z Carlisle.
In the FOURTH article, payment of 200 dollars to his niece, Jenny Rae, daughter of William’s sister Mary Goodman [nee Oliver].
In the FIFTH article, payment of 200 dollars each to his nieces, Harriet Honey and Mary Grace Parnell, daighters of William’s sister Ann Walters of England.
in the SIXTH article, payment of 200 dollars to Oliver Goodman, son of John Goodman now living oin the farm with William’s nephew William M Carlisle (REVOKED)
In the SEVENTH article, for the Executor to sell William’s real and personal property
Codical ITEM 1, pay Oliver Goodman, son of John Goodman, payment of $200 dollars, and 25 acres in College Township.

Probate Court Record of Deaths
Date and place of death, was widowed, from an image of the probate court record of death, entry dated 23 May 1904, from Katia, wife of Tim Grant Oliver, in the email dated 30 September 2022:
Oliver William, Died 1904 March 19th, Widowed, age 93 years 6 months 16 days, Place of Death Gambier, Place of Birth England, Retired farmer, White, Died of old age, Residence of Gambier, Male, Reported by Howard G Yates- Deputy Clerk.
Gambier is 140 miles north-east from where he was residing in Monroe during the 1850 Census. As a reference, Gambier is also 40 miles north-east of Columbus Ohio and 5 miles east of Mt Vernon.

Burial
Dates of birth and death confirmed, place of burial, from a Find a Grave web link to record and headstone photo received from Katia, wife of Tim Grant Oliver, in an email dated 30 September 2022.
https://www.findagrave.com/memorial/34658367/william-oliver
William Oliver
BIRTH: 3 Aug 1810, Lynton, North Devon District, Devon, England
DEATH: 19 Mar 1904 (aged 93), Gambier, Knox County, Ohio, USA
BURIAL: Oak Grove Cemetery, Gambier, Knox County, Ohio, USA
MEMORIAL ID: 34658367

Katia writes in this 30 September 2022 email, that:
“William Oliver was married to Sophia Harris in 1837, probably in Knox Co, OH. They lived most of their married life in Gambier, Knox Co. OH. They had no children but did have Zachariah and Jennie Colwill Carlisle's son, William live with them after his family moved to KS. William Oliver was a Grocer and with the People's Bank of Gambier. Also, Zachariah Carlisle son, Kitto lived with the Olivers and attended Kenyon College”.

Brian of nzolivers found in February 2023, land holdings held by William Oliver and Thomas Harris. It was on Plan 51 (PDF of this map attached), of an Atlas originally published in 1871.
The Atlas is called, "Atlas of Knox County Ohio - From actual Surveys by and under the direction of J.A. Caldwell & J.W.Starr".
It was reproduced in 1980 through the sponsorship of the Knox County Genealogical Society, Mt. Vernon, Ohio.
https://www.ohiohistory.org/wp-content/uploads/202...Knox_County_1871.pdf
Land held by:
William Oliver - two-thirds across, near bottom
Thomas Harris - three-quarters across, half-way down

Entry in the 1860 Free Inhabitants Ohio USA Census enumerated on 16th day of June 1860, for the Monroe Township in the County of Knox Ohio found in February 2023:
Name | Age | Sex | Profession | Value of Real Estate | Value of Personal Estate | Place of Birth
William Oliver, 49, Male, Farmer, $4,200, $600, BornEngland
Sophia Oliver, 48, Female, Born England
Frank Mills, 15, Male, Born Pennsylvania

Entry in the 1870 USA Federal Census for the inhabitants of College Township in the County of Knox Ohio enumerated on 17th day of June 1870, and found in February 2023:
Name | Age | Sex | Color | Profession | Value of Real Estate | Value of Personal Estate | Place of Birth
William Oliver, 49, Male, White, Grocer, $10,000, $1,000, Born England, Father of Foreign Birth, Male Citizen of U.S.
Sophia Oliver, 48, Female, White, Born England
William Carlile, 9, Male, White, Domestic Servant, Born Ohio

Entry in the 1880 USA Federal Census for the inhabitants of College Township in the County of Knox Ohio enumerated on 10th day of June 1880, and found in February 2023:
Name | Color | Sex | Age | Relationship | Single | Married | Profession | Value of Real Estate | Value of Personal Estate | Place of Birth | Father Birthplace | Mother Birthplace
Oliver, William, White, M, 69, Married, Grocer, Can read, Cannot write, Born England, Father born England, Mother born England
Oliver, Sophia, White, F, 68, Wife, Married, Keeping House, Can read, Cannot write, Born England, Father born England, Mother born England
Carlisle, William M, White, M, 19, Grand Nephew, Farm Labourer, sick, Born Ohio, Father born Ohio, Mother born England [Born circa 1861]
Colwill, Minerva, White, F, 20, Grand Niece, Domestic Servant, sick, Born Ohio, Father born England, Mother born England [Born circa 1860]

NOTE: Carlisle, William M in the above Census is William Oliver's wife's sister's (Harriet Harris), daughter's (Jennie Ann Colwill), son, William Mongo Carlisle.
and has the following biography found on Find a Grave in February 2023:
https://www.findagrave.com/memorial/34658972/william-mongo-carlisle
William M. Carlisle married Adelin M. Hanlen 28 May 1885. They had one child, Mary Olive b. 23 Oct 1887 in Gambier, OH. William did not move to KS with his family in the late 1870's but stayed in Ohio living with his uncle, William Oliver. William Carlisle became a successful farmer and was on the People's Bank Board of Directors in Gambier.

NOTE: Colwill, Minerva in the above Census is William Oliver's wife's sister's (Harriet Harris), son's (William Colwill), daughter, Minerva Jane Colwill.

Therefore, William Carlisle and Minerva Colwill are first cousins, sharing the same grandparents, William Colwill and Harriet Harris.

Biographical sketch of William from a link to History of Knox County Ohio received from Katia, wife of Tim Grant Oliver, in an email dated 3 February 2023:
https://babel.hathitrust.org/cgi/pt?id=hvd.hnen4t&view=1up&seq=900
Oliver, William #900 (p.768)
OLIVER, WILLIAM, Gambier, a native of England, was born the third day of August, 1810. At the age of fourteen years he engaged in the mercantile business as clerk, remained two years. In 1826 he commenced working in a flouring mill with his father.
In 1837 he was united in marriage with Miss Sophia Harris, of England, born February 11, 1811.
He continued in the mill with his father until 1840. They migrated to America and located in Gambier, this county. In the spring of 1841 he took charge of the Gambier mills, which he operated successfully until the fall of 1846, when he moved on the farm in Monroe township, this county, which he purchased in 1843. He then turned his attention to farming and butchering, remaining on the farm until 1861, when they moved to Gambier, where they are now living.
He continued the butchering business until 1866. In 1865 he engaged in the grocery trade, and carried on the two branches of business in connection with overseeing his farm, until 1866 and then he gave his attention wholly to butchering, his grocery trade and farming, and continued to do so to the present time.