The old Thornleigh Quarry is located beside the Heritage Trail in Thornleigh, within Berowra Valley Regional Park. The quarry dates back to 1883 and was initially a source of 'ballast' for portions of the Sydney (Homebush) to Newcastle (Waratah) rail link. There is a firm, flat dirt track that leads about 40m from the concrete trail to the centre of the old quarry. You will find a series of log seats in this amphitheatre making this a pleasant spot to sit and enjoy the intriguing mix of nature and history. A book is available with some detail on this quarry and the associated zigzag railway: 'Sydney's Forgotten Quarry Railways' by John Oakes, ISBN 0 9757870 3 9