Moraine or glacial till.

This is known as glacial till.

Coquina is a soft limestone that is formed from the cemented fossil debris of coarse shells and shell fragments. It is a non-foliated rock.

A coarse brush is a brush with stiff bristles or fibers that are thick and rough. It is commonly used for heavy-duty cleaning tasks or for applying thick and textured materials, such as paint or varnish. The coarse bristles are effective for removing dirt, grime, or stubborn debris.

soft in general, easily broken by strong winds