The dating of an ancient well has cast doubt on the research methods behind and scientific basis for the government's decision to preserve it in situ. Some say the decision about the find at the site of a station in To Kwa Wan, on the MTR's Sha Tin-Central rail link, was hasty.
The key question is whether the well indeed dates back to the Song dynasty, as Secretary for Development Paul Chan Mo-po has announced. It could instead have hailed from the Yuan dynasty, which came after the Song.
The confusion arose from an interim archaeological study report that the MTR Corporation submitted to the Antiquities and Monuments Office last month.
The well was part of a "building feature" from the Yuan era, the archaeologists, led by Dr Liu Wensuo of Sun Yat-sen University in Guangzhou, wrote in their 167-page interim report.
"In accordance with the typology of the ceramics unearthed in the feature, [the feature] is dated to the early Yuan to mid-Yuan dynasty," the report said.
The feature consisted of the well, 33 post holes and two wall structures. The distribution pattern of the items also suggested the whole feature came from that period, the report said.
But another part of the report said the well was found below the top of five Song-Yuan sub-layers - with the feature found below the second sub-layer.
Since Liu's team has concluded the feature is from the Yuan era (1279-1368AD), the well, which is higher up, cannot be from the Song (960-1279AD). The lower a layer is, the older it will be.
An industry insider who declined to be named said the well's position backed the report's claim that it was a Yuan relic.
"It is misleading for the report to collectively call the layer 'Song-Yuan' whenever it talks about the well, whereas the sub-layers in fact correspond to different periods within Song-Yuan," he said.
Liu's team began excavation of the relics in and around the To Kwa Wan station site in November 2012. Up to the end of last year, they had unearthed many items dating from between the Song and the 20th century, including seven wells. The well at the centre of the debate was largely intact.
On May 1, the office told reporters it "has been confirmed as a Song-dynasty stone well", despite the report contradicting itself on the dating of the structures. The office also said another well discovered after the report was released was from the Song dynasty, too. The office said: "According to the MTR's archaeologist, the well … belongs to the cultural layer of Song-Yuan period … while both wells are attributed to the Song dynasty."
Mana Tang Hok-sze, a research assistant at Chinese University's centre for Chinese archaeology and art, said the era of relics could be tested by radio carbon-dating. Liu directed South China Morning Post inquiries to the MTR Corporation.