pva glue + sand
black coating
drybrush with fortress grey
drybrush with scorched brown
drybrush with bestial brown
drybrush with bleached bone
pva glue on spots + grass
base painted with scorched brown
(edit forgot the layer of bleached bone...also hint best do the bases in a dozen or so you can brush over all of them at the same time saves on time and nerves.)