 These ridges are the remnants of an ancient, much larger plateau that has been deeply eroded into an extensive series of river valleys.This specific ridge land habitat is particularly significant for Sydney as most similar habitat was left unprotected and was subsequently destroyed to make way for cheap development which has made many species only found ridges threatened with extinction due to extreme habitat clearance/fragmentation.Soils on plateau land are often up to 2m deep and consist of on sandstone ridges