lady orchid was discovered here in 1990, in Nightingale Valley on the west side of the Gorge; there is some doubt as to whether this was a wild plant or an introduction. fly orchid and bee orchid are found in the gorge, along with their hybrid. A single plant of lesser meadow-rue is present in the gorge. Bristol rock-cress occurs here, and at nearby Penpole Point; in the gorge, there are about 3,000 plants on the Bristol side, and about 2,000 below Leigh Woods. Hutchinsia is found on both sides of the gorge. Bloody crane's-bill grows on the Bristol side of the gorge, where it is believed to be native. Little robin occurs on both sides of the gorge. Spiked speedwell grows on both sides of the gorge: the first British record of this plant was from the gorge, in 1641. History of human use The gorge area was inhabited at least as early as the Iron Age, probably by the Dobunni tribe. In Leigh Woods above Nightingale Valley, a steep dry valley beside the suspension bridge, is Stokeleigh Camp, one of three Iron Age hill forts in the area. Stokeleigh was occupied from 3BC to 1AD, and was also used in the Middle Ages. The camp was protected on two sides by the cliff faces of the gorge and Nightingale Valley, and was also protected by earthworks, and is now a scheduled ancient monument. A second hill fort was situated across Nightingale Valley, but has since been built on, and bridge road cuts through it. The third hill fort was situated on the opposite side of the gorge, in what is now observatory green. Archaeology, plus the configuration of the three forts, suggest they played a role in defending the gorge. During the Middle Ages and industrial revolution the area which now forms The Downs was used as common grazing land. It was mined for lead, calamine, iron and limestone, and became home to a windmill which produced snuff from the tobacco which had become one of the city's principal imports. In 1777 the windmill burnt out in a storm, and the building was converted into the observatory, which houses a camera obscura. In the 18th and 19th centuries Bristol's economy boomed and Clifton became a desirable place to live. Mansion houses were built overlooking the gorge, but after grazing was stopped, trees grew and obscured the view from