The video argues Tregiffian’s 13 round and 12 oval cupmarks encode lunar months

May 18, 2026EnglandGeneralShare

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Key facts

• One of the two portal stones at the Tregiffian entrance grave bears 25 artificial hollows, or cupmarks, described as 13 round and 12 oval.
• The video interprets the groups as 13 successive new moons and the 12 full moons between them. This lunar-calendar reading is the presenter’s interpretation, not an established archaeological finding.
• A solar year averages about 12.37 lunar cycles, so the annual number of new and full moons can vary rather than remaining fixed at 13 and 12.
• The cup-marked stone formed part of the entrance above ancestral remains in the grave.
• The video presents a winter-solstice sunset alignment from Chunquoid dolmen to a notch in the Carn Kenidjack cairn.
• The video notes that the solstitial sun’s position has changed by roughly half a degree over 5,000 years, allowing such an alignment to remain effective.
• The video describes an excarnation model in which bodies were placed on dolmen capstones for birds to remove flesh before the bones were buried below.

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