In October 2008 I stopped to collect near exit 28 on Route 80. There was blasting for widening the highway during the summer on the west bound side (north side). There was fill taken from a 60 foot high road cut face placed alongside the cut. This was a window of geological opportunity to look into. The area was going to be inaccessible soon so I was fortunate enough to be there at the right time.
This called area was once called Shippenport not far from the south west end of Lake Hopatcong, located in the Stanhope geological quadrangle. This road cut technically is in Mount Arlington borough, southwestern corner, very close to the boarder to Roxbury, both in Morris County. The coordinates are 400 53” 33” N and 740 39’ 17” W.

REGIONAL GEOLOGY
The area is of Mount Arlington is in the New Jersey Highlands region of the Grenvillian Proterozoic (Pre-Cambrian) basement rock. This area as far as I can ascertain, is affected by the intrusion of the Lake Hopatcong suite, or Byram Suite which intruded into the metasedimentary rocks during the mesoproterozic times. The intrusion of the Lake Hopatcong and Byram granitic rock suites is associated with pegmatites. These intrusions probably transported the Fe and REE into the areas iron mine deposits. As in the case of the BEMCO mine (Charlotte Mine) which is only 9 km NW. Due to the ancient time period, the Grenvillian geology is always being studied and theories area always changing.

Here are some of the specimens I collected in just a couple of hours. There was an amphibolite.

Also there were granitic gneiss, composed mainly of a gray feldspar (possible plagioclase) and biotite.
This is a sample

This specimen seems showed some interesting color under the short wave UV lamp. The green fluorescence is probably indicative of a mineral containing traces of uranium such as hyalite. The yellow minerals may be apatite or less likely zircon. I don’t think it is zircon because the reddish brown zircon taken from the same locality did not fluoresce, and the mineral fluorescing did not appear brownish but rather whitish. So I have another study specimen for the unidentified cache.

The most interesting find was reddish zircon crystals. On examination, they have the typical bipyramidal tetragonal form of zircon. The color, cleavage, association but especially the crystal form points to zircon. They occur in a gray feldspar associated with magnetite. Pieces of which proved to be ferromagnetic. The mineral is surrounded by what appears to be iron stains affecting the surrounding rock.
Here is a 2”x2” sample of the granitic gneiss containing magnetite and zircon along with magnified views of the zircon crystals.

The last two photos show the tetragonal prism {100} faces and tetragonal dipyramidal {111} faces respectively, which is indicative of zircons ditetragonal dipyramidal class. zircon

References:

Proterozoic Tectonic Evolution of the Grenville Orogen in North America
By Richard P. Tollo
Contributor Richard P. Tollo
Published by Geological Society of America, 2004
ISBN 0813711975, 9780813711973

Precambrian Rocks of the Lake Hopatcong Area, New Jersey
DAVIS A. YOUNG

Department of Geology, Washington Square College of Arts and Science, New York University, New York, New York 10003

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