What is (a) Artificial rockwork made of rough stones and cement, as for gardens. (b) The rococo system of scroll ornament, based in part on the forms of shells and water-worn rocks called?

rocaille — (a) Artificial rockwork made of rough stones and cement, as for gardens. (b) The rococo system of scroll ornament, based in part on the forms of shells and water-worn rocks. (Webster's 1913.)

Sources