The most southern outcroj) occurs about a mile north of the Bridge; it again outcrops near the " Club House." This belt probably continues southward into New York Island. The third area of the southern section is a prominent feature of the north end of New York Island, from which it extends three miles northward into Westchester County along Tippitt's Brook. The Harlem River makes a deep cut through it at Kingsbridge; and where the abutments of High Bridge rest, disaj)- pearing there, outcrops at points in Tipj)itt's Valley as far as nearly three miles from Kingsbridge. Just above the point of junction of the Harlem and New Haven Railroads ledges of lime-stone are visible, and were cut into in grading the railroad tracks.

The areas of serpentine, with some calcareous material, ajjpear at New Rochelle and Rye. At Yonkers the lime-stone area follows the course of a north and south bend on Saw-Mill Creek, with a width of at least one hundred feet. There are indications of a more eastern belt along the Saw-Mill River Valley just north of the city. On Gnissy Sprain Brook a small area exists with a width to the south of live iiundred yards. On the IJronx River a lime-stone belt begins near Bronx ville, and taj)ers out to the south, while to the north, and for the most of its course, it is divided into two parts, separated by a band of mica-sihist and gneiss. The Hastings belt occurs along the Hudson to the north of Y(mkers.