Augustus was the one that was concerned with marking the Empire's borders
The answer is;
A) the history of the Aztecs, C) the civic duties of citizens and D) the art of warfare
The central government didn't have the power to tax the states
Keeping in mind the description of the stone point given in the story, we can state Marshall the rancher was looking at a Folsom point.
As it's known, a Folsom is a kind of stone point with a leaf-like shape which has a concave base and wide, shallow grooves/flutes running almost the entire length of the point.