The narrow left side of Avebury Stone #16 (looking henge outward) marks stars to the left of the previously deciphered Virgo on the henge outward face.
Avebury Stone #16 Left Side Photograph and Tracing by Andis Kaulins
-- click on the graphic for a larger image --
Avebury Stone #16 Left Side Photo Tracing in Black/White, Color and Stars
The left side of Avebury Stone #16 points toward Leo and marks Leo in the stars as a lion head together with Ursa Major as a dog-like animal above it, plus Leo Minor viz. Lynx as another "big cat" or cub, and below Leo there are stars of Hydra marked as a large serpent plus a smaller serpent.