The term SOMETHING FOUND IN SEAMS can be solved by the four-letter word COAL. COAL is a combustible black or brownish-black sedimentary rock, formed over millions of years from the remains of plants that were buried and exposed to geological forces. It is primarily used as a fuel source for electricity generation and steel production. COAL is also found in seams, which are thin layers of COAL that are found between other layers of sedimentary rock.