Passenger Lists are held the National Archives: More about these records can be found at
www.nationalarchives.gov.uk/familyhistory/guide/.
Have you looked at the ISTG - Immigrants Ships Transcriber's Guild, ongoing but you might be lucky.
Here's the passenger list link [numbers are the numbers on the manifest]:
http://immigrantships.net/v9/surnamesv9/splgel_v9.htmLocal Papers US or UK are often a good source of information of sailings - sometimes passengers occasionally mentioned arriving. Would Oliver have traveled with his father or another family member? Which Port did he arrive at?
This is not exactly your question, but did Oliver stay in the UK if so he may have obtained Naturalisation - docs held at the Home Office and published in the London Gazette.
On 1881 Census there are more Evans next door, says (son / Head) I'm assuming it's Ann Evans son:
Household:
Name Relation Marital Status Gender Age Birthplace Occupation Disability
William EVANS Son (Head) M Male 24 Languicke Parish Of Collier
Margaret EVANS Wife M Female 24
Source Information:
Dwelling 13 Companys Houses
Census Place Llanguick, Glamorgan, Wales
Family History Library Film 1342288
Public Records Office Reference RG11
Piece / Folio 5347 / 81
Page Number 45
Have you tried looking for 1873 birth record for Oliver? Should give father's name.
If father's name was Evan there is an Evan J Evans on US 1880 census:
Name Relation Marital Status Gender Race Age Birthplace Occupation Father's Birthplace Mother's Birthplace
Evan J. EVANS Self M Male W 43 WALES Gold Miner WALES WALES
Jane EVANS Wife M Female W 46 WALES Keeping House WALES WALES
Obediah EVANS Son S Male W 19 WALES Gold Miner WALES WALES
Source Information:
Census Place Placerville, El Dorado, California
Family History Library Film 1254065
NA Film Number T9-0065
Page Number 129B
He may have sent his youngest to Wales to get him out of the rough life of the gold fields and get him and education???
There is also a single 33 year old single man in Bodie California as a labourer. The only Bodie CA I know was a silver mining town (now deserted) - don't know for sure if it was going in 1880, but I think so. If he had Oliver by a lady of the town he might have sent him home to Wales.
There are quite a few Evan Evans on 1881 census. To establish the family names, if Ann Evans is aunt, I'd be looking for an Evans marriage to an Ann from Camarthan - (around place and date of Wm Evans birth in 1857, but could be Camarthan too), then trace her husband's parents & siblings. Hopefully a brother will emerge who is Oliver's father. Try an IGI search.