This National Nature Reserve is currently closed to the public. Main habitat: geology As a sensitive fossil site located on a privately owned industrial estate, access to Horn Park Quarry is controlled and requires prior arrangement with Natural England. To arrange a visit, contact the senior reserve manager on 07899 731404. Features of interest Horn Park Quarry is the smallest NNR in Britain, being just one acre or 0.32 hectares in size. The exposed strata belong to the Aalenian, Bajocian and lowest Bathonian stages of the Middle Jurassic, deposited between approximately 188 and 175 million years ago. Collectively these strata constitute the Inferior Oolite series. The reserve is important because it contains the most complete Aalenian ammonite succession known to date in England, with all four Aalenian ammonite zones being present. It is an internationally important site for the study and correlation of Aalenian rocks throughout Britain and across Europe. The limestones contain an extremely diverse and well preserved fossil fauna dominated by ammonites and bivalves. One of the most spectacular features is the ‘fossil bed’ - a layer packed with ammonites, bivalves, brachiopods, sponges and fossil wood which lies sandwiched between other, less fossiliferous strata. Contact For more information about the reserve contact Natural England Enquiries, telephone 0300 060 3900, email enquiries@naturalengland.org.uk