Answer:
The historian should consult a Geologist or a Geographer.
Step-by-step explanation:
The Geologist would explain how the topography of the region would help this civilization to shape its culture, how the valleys and mountains promote the social structure. And the Geographer would help the historian to understand how this society understands the natural elements, the geography of their surroundings and what these points were crucial for their establishment. Based on these answers, the historian can create his/her analysis.