The gray blocks behind the peons are rock resources


Rock is an essential resources to make rock and chicken warriors.  For a rock warrior one rock and two wood resources are needed.  Rock can be found throughout any given map.  It is the grayish blocks on the ground.  Now rock is not needed as much as iron or chicken or wood however having some is not a bad thing.  If you are running low on chicken or iron you should use your stored up rock to make rock warriors.  It could save your tribal trouble life someday.