Ilkley Quarry is the site of the famous "Cow and Calf", a large rock formation consisting of an outcrop and boulder, also known as Hangingstone Rocks. The rocks are made of millstone grit, a variety of sandstone, and are so named because one is large, with the smaller one sitting close to it, like a cow and . Legend has it that there was once also a "bull", but that was quarried for stone during the spa town boom that Ilkley was part of in the 19th century. However, none of the local historians have provided any evidence of the Bull's existence.