34000 Year Old Lunar Calendar

A bone tablet discovered in Dordogne, France, is an accurate lunar calendar carved during the Aurignacian era 34,000 years ago.

34,000 years… pic.twitter.com/xLVGHxyAeD

— Brian Roemmele (@BrianRoemmele) September 8, 2026

But what about the notches around the periphery?

According to Alexander Marshack’s widely referenced analysis, the notches (grooves) along the edges form part of a sequential notational system for tracking lunar time.

Roughly 63 notches have been identified along the perimeter. Marshack interpreted these as marking a three-month interval that begins with the last visible crescent moon and ends with the night of the new or invisible moon. When combined with the internal marks (crescents, dots, and other incisions arranged in a serpentine pattern), the total count of notches and engravings on the plaque is around 172. This roughly corresponds to about six lunar months (≈177 days at 29.5 days per cycle) or roughly two seasons.

The edge notches are therefore seen as an integral part of the portable “calendar” or time-reckoning device rather than purely decorative or structural features. They helped structure the cumulative record of lunar phases observed over successive cycles.Some later commentators note that notches appear along three edges and leave open secondary possibilities (e.g., a scale related to the main diagram, or marks referring to the reverse side of the bone). However, the primary and most cited interpretation remains Marshack’s: the perimeter grooves contribute to the overall lunar-notational system of this ~34,000-year-old Aurignacian artifact from Abri Blanchard.