Some scientists have studied several existing nautilus fossils and found that the wavy threads on their shells have the same function as tree rings, and the threads are divided into many spaces  although they are different in width and width, there are about 30 small wavy growth lines in each interval, which is exactly the same as the number of days in a month in the modern lunar calendar  It is found that the wavy growth line of Nautilus grows one every day and one interval every month
Moreover, there is a lot of scientific evidence that the moon is gradually moving away from the earth, and the lunar calendar is the number of days for the moon to circle the earth
The number of growth lines per interval of the ancient nautilus gradually decreased with the dating of fossils