Usually with pieces like this I complete a lot of the main design before linking them together with some decorative elements, such as leaves etc, at the end ~ this time I thought it best to draw a line under the two areas on the front and side of the tree stump, and so worked on the background design before moving on to the Roman helmet.
I found some illustrations of archaeological finds, where the different layers of earth were shown as wavy lines with small shapes representing stones here and there, and adapted that idea for the Jurassic background.
The zig-zag pattern was used for the Stone, Iron and Bronze Age background, as it has been used as a style of decoration for as long as Man has embellished his home, weapons, utensils and vessels.
I’d earmarked a round area near the top of the stump for the next item, a Roman helmet.
A good start, more tomorrow!