Tarr, of Cornell University, in a recent series of papers1 on the geology of New York State, embodying the latest investigations and conclusions on the subject, assigns to the southern angle of the State, including Westchester County, the name of the " Gneissic Highland Province." This province, he says, is of complex structure, and one in which, in its main and most typical part, the rocks are very much folded and disturbed metamorphic strata of ancient date. " These rocks/' he continues, " are really an extension of the highlands of New Jersey, which reach across the southern angle of New York, extend northeastward, and enter Connecticut. Besides these Archean gneisses there is some sandstone and a black diabese or trap, which form the Palisades, besides extensive layers of limestone, gneiss, and schist, which extend across the region occupied by the City of New York. This whole series of strata is intricately associated. Except at the very seashore line, the province is a moderate highland, with rather rough topography and with hills rising in some places to an elevation of 1,000 or 1,200 feet above the sea level. Where there is limestone or sandstone in this area, there is usually a lowland, while highlands occur where the hard gneiss comes to the surface not immediately at the seashore. This is extremely well illustrated in Rockland County, where the gneissic Ramapo Mountains are faced at their southeastern base by a lowland, a somewhat rolling plain, which, however, is bounded on its eastern margin by another highland where the trap of the Palisades rises close by the Hudson River/' In the opinion of Professor Tarr, this region, with the large Adirondack area, at the beginning of the Paleozoic were mountainous lands facing the sea, which stretched away to the westward, and beneath which all the rest of the site of New York State was submerged.