Figure 11. Gulf lines LS50 to LS52, showing the arching of the Puerto Rico-Virgin Islands carbonate platform seen in the Virgin Islands area. There is a smooth northward dipping slope in the north, a flat eroded area in the middle, and a steeper dipping slope in the south. Notice the two unconformities in the north of the area. Both the middle Eocene-early Oligocene sediments and the early Oligocene-early Pliocene platform are truncated by angular unconformities related to arching. (b) Interpretation of Gulf lines LS50 to LS52. Inset shows location of Gulf lines LS50 to LS52.