It also marks the end of a story, unless more information comes to light.
Pam and John Chapman, of Earnscleugh, own Coma Villa Estate, which used to belong to the infants’ parents — miner, grape grower and businessman Thomas Oliver and his wife, Mary Ann (nee Osborne), in the 1860s and 1870s.
Mr Chapman made the cross from Australian hardwood and they added a small inscribed plaque.
"It gives a bit of closure," Mrs Chapman said.
Mr and Mrs Chapman bought the Coma Villa property in 1982 as a farm and, a year later, Mr Chapman’s tractor wheel went through a hole in the ground into what was an old wine cellar. It stored empty wine bottles, among other relics, which indicated there was a vineyard and winery on the property, and possibly one of the first in the district.
The discovery encouraged the couple to re-establish the vineyard and winery under the Coma Villa label.
They and former Alexandra historian Wayne Stark, now of Christchurch continued to research the family, using existing material by historian Dr John McCraw.
The Chapmans visited Los Angeles last year to see if they could find out what happened to the Oliver descendants, but the trail ended in 1933.
"Now we have found as much as we can possibly find [about them]," Mr Chapman said.
However, they are keen to hear from anyone who might have more information.
"Otherwise, we have come to the end of the story," Mr Stark said.
Thomas Oliver arrived in the district from England during the gold rush in the early 1860s.
He and two business partners made money building water races to supply water to the miners before selling up and moving his family to Dunedin to run the Sussex Hotel.
He left for California in 1896.