From introduction: The North Coast Limestone area is one of the two most important ground-water provinces of Puerto Rico--the other being the South Coast Alluvial aquifer. The investigation of the water resources of the South Coast has progressed to the point that at this time (mid-1971) an electric-analog model of the area is being prepared. The hydrology of the North Coast Limestones, however, was never investigated as a whole before this investigation, and, therefore, this study was designed to assess the most important hydrolic features of the area.