1 Rudist bivalves in Jamaica: from Barrett and Sawkins to Chubb Simon F. Mitchell and Sherene James-Williamson Department of Geography and Geology, The University of the West Indies, Mona, Kingston 7, Jamaica. The Discovery of Rudists in Jamaica Rudist bivalves were discovered in Jamaica early during the First Geological Survey, a survey commissioned by the Colonial Government in Jamaica and the Home Government in London that was undertaken to determine the economic mineral resources of the island. The director of the survey, Mr. Lucas Barrett, and his assisitant, James Gay Sawkins, began their survey in St. Thomas in the East (now the Parish of St. Thomas), and in the banks of the Plantain Garden River, some 3 miles west of Bath, they discovered several thin limestones that contained specimens of Cretaceous fossils included hippurites (not Barrettia, as is often stated, but rudists sensu lato, since the Ŷaŵe hippuƌites ǁas at that tiŵe used foƌ ŵost rudists), Inoceramus and Nerinaea, and demonstrated that these rocks were of Cretaceous age (Barrett, 1860). The founder of Jamaican Geology, Sir Henry De la Beche, had formerly mapped the area and had included the rocks in which the rudists were found as the Transition Series which was then attributed to the Palaeozoic (De la Beche, 1827); but even De la Beche (1830) whould admit that this age was based on gross mineralogy and had little value. Yet the notice published in the Quaterly Journal of the Geological Society by daƌƌett ǁas Ŷot the fiƌst fossil ƌeĐoƌd that De la deĐhes suggestions of age were wrong, for James Gay Sawkins had reported a Cretaceous coral (Caryophyllia centralis) in rocks below the so-called Coal Measures several years before (Sawkins, 1856). After mapping St. Thomas in the East, Barrett and Sawkins split up – Sawkins would survey the eastern part of the parish of Portland, whilst Barrett would survey the western part of the same parish. It was Barrett, whilst exploring the western area of the Back River (Back Rio Grande) who discovered a limestone in January 1861 with the remarkable fossil that once transported back to England, and investigated by S. P. Woodward (1862; Figure 1), would be described as Barrettia monilifera (the generic name Barrettia was taken from Barrett, although apparently much to his dislike: Annonymous, 1863). Barrett died at the end of 1862 in a diving accident and Sawkins was promoted to Director of the Survey. The Director of the Geological Survey for the survey of Trinidad which was undertaken before that of Jamaica, George Parks Wall, was in Jamaica (probably involved with the Jamaican copper mining companies), and was temporarily employed in the position of Assistant Geologist. Wall had made extensive collections of corals (Duncan and Wall, 1865) and rudists (Chubb, 1980) in Clarendon, and upon leaving Jamaica he took these specimens back to London where they were lodged in the British Museum. Sawkins, together with his assistants – George Parks Wall, Arthur Lennox, and Charles Barrington Brown – were also to make collections of fossils including rudists, but lack of resources in the colony of Jamaica and/or from the Colonial Office in London meant that none of these specimens was ever sent to London (Sawkins and Brown, 1867). These specimens, which were subsequently referred to as the Sawkins and Brown collection, were used to establish a Geological Museum in Spanish Town in 1866 or 1867, and in 1879, with other collections, went to form the nucleus of the Institue of Jamaica (Kaplan, 1996). Figure 1. The original cross-section of Barrettia monilifera Woodward (1862, plate II, fig. 5). This section (which can no longer be traced) shows the two pillars, the posterior myophore fitting into a socket, and the two teeth fitting into slots. Mitchell (2010, fig. 6B) illustrated an almost identical specimen from the type locality.