by The National Trust. The grassland and gorse scrub is criss-crossed with footpaths and is home to many species of butterflies and birds, notably nesting European stonechats. The Knavocks, like other coastal heathlands in Cornwall, is managed by regularly cutting back the gorse and by grazing, the National Trust having introduced a herd of ponies for the purpose. Beyond Fishing Cove, the coast swings to the east towards Hell's Mouth and North Cliffs. The land here rises to approximately , the highest point on this section of clifftop. The cliffs, offshore rocks and coast around Godrevy Head form a renowned habitat for seabirds including cormorants, fulmars, guillemots, and razorbills and several species of gull. There is also a substantial population of grey seals throughout the year. Occasionally, bottlenose dolphins can be seen in the area. Godrevy Island and The Stones Godrevy Island lies approx three hundred yards off Godrevy Point. The uninhabited island is the site of Godrevy Lighthouse, operated by Trinity House. The island covers an area of and is home to seagulls, oystercatchers and pipits. Its vegetation is dominated by grasses, with primroses and sea thrift flowering in the spring. Landings may only be made on the island with the permission of Trinity House. Seaward of Godrevy Island is a submerged reef known as The Stones which extends for approximately to the northwest across the eastern approach to St Ives Bay. It has been the site of many sinkings over the years but it was not until the disastrous loss of the SS Nile on 30 November 1854, with the loss of all aboard, that Trinity House was pressured to construct a lighthouse on the island. It was built in 1859 and was converted to fully automatic operation in 1939. Geology The rocks at Godrevy are Devonian mudstones overlain with Quaternary ice age deposits. The mudstone was laid in a deep sea sedimentary basin and subject to seismic activity, forming turbidites. Under gravitational slumping the coarser material settled first followed by the finer material. Overlying the turbidites are a sequence of rocks laid down during recent ice ages, and Godrevy is considered to be one of the most important Pleistocene (2,588,000 to 11,700 years ago) sites in the south west of England. Mammal fossils are rare in Cornwall and a dog was found within the poorly sorted, coarse-grained sediments of head dated between 12,000 and 15,000 years ago.