The regionally metamorphosed rocks of Jamaica consist of parallel high- and low-grade belts that trend northwest. The low-grade belt — the Mount Hibernia Schist complex — consists of fine-grained schist and marble containing tremolite and actinolite, chlorite, and epidote. At the eastern end of the low-grade belt, crossite- and stilpnomelane-bearing schists are found. The low-grade belt is separated from the high-grade belt — the Westphalia Schist complex — by a major fault zone. The mineralogy of the low-grade belt and its position relative to the high-grade belt may suggest that a southwest-dipping subduction zone existed in eastern Jamaica in Cretaceous time. The position of these rocks is anomalous with respect to similar occurrences in the other islands of the Greater Antilles and is not explained by any existing tectonic models of the evolution of the Caribbean.