Over 90% of the parish's surface is limestone so there is an abundance of cockpits, sinkholes, caves and underground passages. Gourie Cave, near Christiana, is the longest of the over 100 caves in the parish, as well as the longest known cave in Jamaica (3505m). Smokey Hole Cave, in Cross Keys, is the deepest known cave on the island (194m). Oxford Cave, near Auchtembeddie, in the NW part of the parish, is another of the major speleological sites found in Manchester, and was once noted as a roosting site for the now possibly extinct bat species "Phyllonycteris aphylla". Manchester also has large bauxite deposits, with parts of the parish having been strip-mined as a result, notably in William's Field, Hope and Blue Mountain.