Area: 2.64 hectares.
The site was formerly known as Dunchideock Old Quarry.
Description and Reasons for Notification:
The northern Quarry of the pair in this area exhibits about 15 m of a porphyritic basalt lava of Permian age. Together with various lamprophyres, these early basaltic extrusives were dominant expressions of post-orogenic Permian vulcanism. Of particular interest here is the highly vesicular base of the lava which incorporates fragments of reddened sediment. The intimate association indicates that the lava flowed into and over wet unconsolidated sediments.
The dense scrub growing on the floor and slopes of the quarry supports a number of species of butterfly, including the silver-washed fritillary Argynnis paphis, white admiral Limenitis camilla and the brown hairstreak Thecla betulae.