The early marble and limestone headstones have fared poorly; some are unreadable. Here on the near west side, near Cleveland's industrial valley with its steel mills and oil refineries, and the use of coal for heating and later to generate electricity, dirtied the air. Later came auto emissions from the nearby highways. What we now call "acid rain" has dissolved the surfaces. Granite stones, which began to be used in the 1900s, offer much more resistance to erosion, as can be seen at the newer Mayfield Cemetery which is also favored by its greater distance from the city's industrial valley and its higher altitude.