The Blue and John Crow Mountains National Park conserves about 78,000 hectares of tropical rain-forest in the north-east of Jamaica. These forests cover the steep mountain slopes (mostly over 1,000 metres) in the interior of the parishes of St. Andrew, Portland, St. Thomas and St. Mary. The geology of the Blue Mountains is shale, whilst that of the John Crow Mountains further to the east is limestone. Both mountain ranges are unique in the island due to their geology, elevation and rainfall. The forests of the Blue and John Crow Mountains National Park are world renowned for their biological diversity and many researchers come to explore and study the area.