Thanks for your answers. Another quick question (because I'm not perfectly familiar with english language and sometimes I am confused when I am trying to understand game mechanics from Ring of Brodgar).
Question about cave clay: `Cave Clay can be found on cave tiles as quite a rare spawn` - this means that this clay can be mined from the walls or can be picked up only like Gray Clay? Also - this clay can be found even in 1 lvl of the cave ?