slickrocks

/ˈslɪkˌrɑks/
noun
  1. Smooth, often slippery rocks, typically found in or near water.
    • After the tide went out, the beach was covered with slickrocks covered in seaweed.
    • Hiking along the river, we had to avoid the slickrocks to keep from falling.
    • The children carefully stepped across the slickrocks in the shallow stream.