54 TRANSACTIONS OF THE [JAN. 7, 
8. Amphibolites.—True, garnetiferous, marcasitic, saccha- 
ritic, scapolitic; gneiss amphibolite, and epidote amphibolite. 
9. Granite.—This granite is sedimentary and not eruptive; 
so-called ‘‘ Lagergranite.” The varieties are muscovite, biotite, 
bio-micaceous, tourmalinic, and coarse granite. Pegmatite. 
10. Gneiss.—Muscovite, biotite, micaceous, sericitic, albite, 
amphibolite, epidote, calciferous, garnetiferous, tourmalinic, 
magnetite, and giant gneiss. 
11. Gabbro.—This is found in one locality only—in 100th 
street, between Lexington and Fourth avenues. 
Veins. These consist of quartz, albite, calcite, chabazite, 
iron ores—limonite, marcasite, and magnetite,—quartzite, coarse 
granite, pegmatite, and a metamorphosed magma, consisting of 
the detritus or remnants of epidote and protochlorite schist. 
The composition of this last class of veins demonstrates plainly 
the nature of its genesis, having been formed from above or in 
faults and intervening spaces. These vein-constituents occur 
individually, or associated with a certain regularity, and accom- 
panied by a specific group of minerals. For instance, chabazite 
may occur singly, but it is generally associated with quartz, 
albite, calcite, limonite, and marcasite; these minerals occur 
massive, but often in beautiful crystals, especially chabazite is 
represented by all its known varieties good specimens of phaco- 
lite are common, and pseudomorphs of limonite after phaco- 
lite. 
Lithological Belts or Regions : 
1. Serpentine. ‘This region is limited between Ninth avenue 
and the Hudson and between 57th and 60th streets. 
2. The dolomite belt is predominant at the northern ter- 
minus of the island. 
3. The typical New York Island or Gneiss Belt comprises the 
lower two-thirds of the island. There are only a few varieties 
missing, and there is scarcely a locality which is more favorable 
the study of gneisses. 
4, Albite, Epidote and Protochlorite Belt, with specific 
ores (pyrite, pyrrhotite, magnetite [also in crystals], limonite, 
and ilmenite) and traces of serpentine. The limits are 95th and 
102d streets, and Third and Fifth avenues. From this region 
are specimens of albite and epidote, as fine as those found in the 
Austrian Tyrol. 
Conformability. There is conformability between the gneisses 
and mica schists, and unconformability between gneiss and ser- 
pentine and between mica schists and amphibolites. 
Dip. The direction of the dip varies as much as the angle; 
the bottom rock along the Kast River between 72d and 42d 
streets is almost horizontal, while on the west side, between 80th 
