Dumb symbology question

[1940LaSalle]

In certain tiles, one often sees small stone-like objects that don't warrant identification under "Terrain Information" (i.e., they're not identified as some strategic resource). What the heck are they?

 

[tao]

I suppose you mean bonus grassland, i.e. +1 shield.

 

[Marsden]

Maybe you have "show food and resources on map" activated?

 

[Tasslehoff]

They're almost definitely "bonus" grassland tiles, with small white dot-like shapes. They give the grassland an extra shield.