Benjamin LEWIS was born 1829 at Wales, England.
Mary EDWARDS was born in 1832 at Wales, England

The 1841 England, Wales & Scotland Census has the following:
At Hirwain Aberdare, Merthyr Tydfil, Glamorganshire, Wales
David LEWIS b.1796
Mary LEWIS b.1796
John LEWIS b.1821
Benjamin LEWIS b.1829
Josiah LEWIS b.1834
Owen WILLIAM b.1816
Josapth HOWELLS b.1826

The 1851 England, Wales & Scotland Census has the following:
At Hirwain Castle, Aberdare, Merthyr Tydfil, Glamorganshire, Wales
Mary LEWIS, widow, Baker, b.1793, at Llanmihangel, Carmarthenshire, Wales
Benjamin LEWIS, unmarried, Collier, b.1829 at Aberdare, Glamorganshire, Wales
Catherine JONES, grand-daughter, unmarried, Scholar, b.1844 at Aberdare, Glamorganshire, Wales
Joseph GRIFFITHS, lodger, unmarried, Jorn Miner, b.1812 at Carmarathenshire, Wales

Benjamin LEWIS m. Mary EDWARDS in 1853 (4th quarter) at Merthyr Tydfil district, Glamorganshire, Wales

Benjamin LEWIS and his wife Mary LEWIS (nee EDWARDS) came to South Australia on the ship 'Taymouth Castle', leaving from Plymouth 7 Feb 1854, arriving at Port Adelaide on 3 May 1854. Benjamin's occupation was listed as 'miner' and his age 25 and Mary's 22. They were from Wales.

I have not been able to discover anything about their movements from 1854 until 1859. In the Friday 4 Nov 1859 edition of The South Australia Advertiser, Benjamin is listed as the intending purchaser of a Residence in Littlehampton from George Wright. Lots 72, 73, 74, 75 Littlehampton, of Section 5010.

Benjamin LEWIS died 11th February 1897 (68yrs) at Littlehampton, South Australia
Mary Nash LEWIS died 22nd August 1905 (75yrs) at Littlehampton. (deceased Husband Benjamin LEWIS)
Also Sarah Nash LEWIS died 22nd Aug 1905 (75yrs) widowed, at Littlehampton (deceased Husband Benjamin LEWIS)
Note: same date of death, same deceased husband, Mary was known as Sarah.

Children of Benjamin LEWIS & Mary EDWARDS
1. Margaret LEWIS b. 24 Aug 1854, Adelaide m. Joseph Sheppard FIDLER
2. Elizabeth LEWIS b. 14 Aug 1860 at Littlehampton m. John HAMILTON
3. Hopkin LEWIS b. 5 Oct 1862 at Littlehampton m. Elizabeth CHAMBERS
4. Benjamin LEWIS b. 3 Feb 1868 at Littlehampton m. Florence Naomi THOMAS
5. Amy LEWIS b. 23 May 1870 at Littlehampton m. James Alfred CHILDS