76 TRANSACTIONS OF THE [Jan. 23 
This occurrence of norite, although clearly restricted in area, 
is interesting for several reasons. It indicates in the first place, 
an outcrop of this rock in the extended interval between Peeks- 
kill on the north and Baltimore on the south, which was not 
hitherto known to contain it. In Volume I of his Final Reports, 
pp. 107-108, Professor Lesley remarks, with some surprise, on 
the absence of the ‘Labradorite” rocks or Norian in this 
Archzean belt. The rocks here mentioned are entirely analogous 
to many in the Adirondacks. But I would not wish to imply 
anything of their geological age from their mineralogical 
composition. They may be merely an intruded knob or large 
dike. We have also in the Columbia College collections a slide 
of a rock, which was collected by Dr. Britton from a cut on the 
Ogden Mine Railroad north of Minnesink, N. J. It is a well 
marked gabbro with a little hypersthene. The slide shows 
plagioclase, green monoclinic pyroxene, greenish hornblende, 
magnetite, apatite, and the little hypersthene referred to. 
Probably other occurrences will be found in the great exposures 
of the crystalline rocks of the Highlands. R. W. Raymond 
has called attention to titaniferous ores in New Jersey at the 
town of Bethlehem. (See discussion of paper by H. B. C, Nitze 
on ‘‘ Magnetic Iron Ores of Ashe County, North Carolina,” at 
the Baltimore meeting of the Institute of Mining Engineers, 
February, 1872.) It would be quite natural from what we 
know of these ores in the Adirondacks and in Sweden to find 
them associated with rocks of the gabbro family. 
The second interesting point is that the minerals in the 
limestone at the quarry are probably the result of contact 
metamorphism wrought by the plutonic rock mass on the 
neighboring limestone. While much the same series occurs in 
the regionally metamorphosed linestones of Canada and else- 
where, where no igneous rocks have been mentioned, the list 
does present some striking similarities with those which have 
been formed by contact action or limestones in many parts of 
the world. Although few cases are recorded where these effects 
are due to rocks of the gabbro family, we have descriptions of 
many such contacts of diorites, syenites and diabase in the 
Tyrolese Alps, with which the Austrian geologists—Tschermak, 
Reyer, Lepsius, and others—have made us familiar. Many of 
the minerals mentioned above appear there, but in Pennsyl- 
vania we lack vesuvianite, which is often characteristic of such 
surroundings. G. H. Williams found at Stony Point on the 
Hudson, a narrow strip of limestone between mica-diorite and 
peridotite. It contained malacolite, light green hornblende, 
zoisite, Sphene and scapolite. We have all of these except 
