I think I already posted this half a dozend times somewhere here on the forum ;-)
Those icons show the presence of a known (level-0) site in the province.
=> When the game rolls for sites, it puts on automatically into the province when it encounters those terrain numbers.
Code:
Decimal Bitmap (3byte?) 2^x Terrain
Number 321098765432109876543210
8192 000000000010000000000000 ="firesite" (vulcano)
16384 000000000100000000000000 ="airsite" (?)
32768 000000001000000000000000 ="watersite" (lake)
65536 000000010000000000000000 ="earthsite" (?)
131072 000000100000000000000000 ="astralsite" (?)
262144 000001000000000000000000 ="deathsite" (house)
524288 000010000000000000000000 ="naturesite" (tree)
1048576 000100000000000000000000 ="bloodsite" (????)
2097152 001000000000000000000000 ="priestsite" (standingstones)