Isolated siliceous sponge spicules recovered from deep-water chalk in the Lower Miocene Montpelier Formation (White Limestone Group) were collected from the lowest exposed beds at Duncans Quarry, parish of Trelawny, Jamaica. Megascleres include a variety of normal calthrops, a dichotriaene and a triaene, associated with an astrose sphaeraster microsclere. Because these spicules appear as common elements in the order Choristida of the class Demospongea, identification below order is not possible, and all the spicules may have come from one species of choristid sponge. A single pentactine also occurs in the collection. This spicule may be either from a demosponge or possibly a hexactinellid. The only other known reports of White Limestone sponge spicules (class Hexactinellida) are from the Pelleu Island Formation (formerly the Spring Garden Member of the Montpelier Formation).

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Cainozoic research

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Roger W. Portell, & J. Keith Rigby. (2003). Sponge spicules from the White Limestone Group of Jamaica. Cainozoic research, 3(1/2), 77–81.