An intact chamber pot, an ornate salad oil bottle, and century-old “Frozen Charlotte” porcelain dolls were among thousands of 150-year-old artefacts discovered underground on a central Christchurch site.

The historic items, some dating back to the 1850s, were discovered during an archaeological dig on an empty site on the corner of Tuam St and Oxford Tce.

The archaeologists also found brick foundations, numerous Victorian rubbish pits, hundreds of intact glass bottles, and a corrugated fence line.

Frozen Charlotte dolls were popular in the United States in the mid-1800s and got the name as they resembled corpses, according to the Washington Post. The name was based on a folk tale about a vain woman freezing to death while travelling to a ball in an open sleigh.

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Southern Pacific Archaeological Research (SPAR) director Richard Walter said they were surprised by the quantity and diversity of the historical items found on the site.

He said they removed as many as 70 plastic storage bins full of historic items, which represented a tiny percentage of the artefacts buried on the site.

“This is an extremely rich site,’’ he said.

“We weren’t expecting this much material and the diversity of the material is really interesting.”

The site was once home to the Christchurch Ladies’ School, which was opened in Avon House in March 1854 by early settler Maria Thomson. Walter said items were found on the site that may have been used at the school.

"This site relates to a very important time period with the establishment of Christchurch as a major city.’’

SPAR archaeologist Tristan Russell said the site could have once contained some of the first buildings in the city.

“The 1854 deed ... suggests that two earlier buildings were present on the northwest portion of the project area prior to Avon House. These buildings would be among the earliest established in Christchurch.”

Russell said the items would be analysed to establish when they were made and where they came from.

“Features such as maker’s marks on ceramic vessels, forms of glass bottles and embossing, as well as stamped marks on hand-made bricks, can all be linked to specific periods of manufacture and use, which will be used to develop a narrative of the European-influenced history of the site.

“These connections can form narratives that can shed light on early European occupation of the site, as well as inform themes such as gender, status, foodways and lifeways.”

Russell said the site was also an important mahinga kai (food gathering place), used by Ngāi Tahu for hundreds of years.

But he said they found no “archaeological evidence relating to Māori activities prior to the European settlement of the area’’ on the site.

The archaeological dig was completed ahead of construction work to build a new $220 million University of Otago campus on the site.