LEVISON, NEWARK IGNEOUS ROCKS 
123 
These appear to be analyses of typical trap rock, not of the special sheets 
and fragments which occupy the joints in the diabase, or the fragments 
which make up the breceiated facies, or the material of the amygdaloidal 
or vesicular trap which seem most productive of trap minerals. From these 
analyses, however, trap rock appears to contain all the constituents usually 
found in the common trap minerals, with the singular exception of boron, 
which is a principal constituent of datolite and fluorine, and of which 
apophyllite generally but not always contains a small proportion. Datolite 
is a basic orthosilicate of boron and calcium 1 which occurs liberally in some 
of the New Jersey cpiarries, sparingly or not at all in others, usually directly 
upon the trap. 
The origin of the trap minerals, as well as many others, has long been 
attributed to the action of water, by some under ordinary present tempera¬ 
ture conditions, 2 by others to magmatic water and hydrothermal processes. 3 
In the New Jersey trap the frequent occurrence in cavities or parts of fissures 
of the remains of previously formed crystals now apparently undergoing 
solution and in close juxtaposition thereto of exquisitely perfect crystals 
both microscopic and macroscopic in beautiful groups, apparently now in 
process of development, seems to indicate that water under present condi¬ 
tions is still actively engaged in both their dissolution and their generation. 
Some interesting results apparently of these contending processes occur in 
crystals of calcite at Upper Montclair, N. J., consisting of etchings and 
oscillations of growth. Such a crystal is shown in Plate XI, Fig. I. 4 
Probably both rain and spring water take part in the production of trap 
minerals. With reference to the solubility of New Jersey trap in meteoric 
water, the following experiment is of interest: A quantity of hard trap rock 
from a quarry at Upper Montclair, N. J., broken into pieces about 6 mm. in 
diameter was washed free from dust with distilled water and air-dried on 
filtering paper. Then 100 grammes of this broken stone was submerged in 
200 cc. of distilled water in a covered glass jar. It was frequently stirred, 
and the water gradually became turbid with floceuli of a dark greenish color. 
Sixteen days later the water was poured off the trap rock, each piece of the 
latter washed with a jet of distilled water, the solution and wash water 
filtered and then evaporated at 100° C. in a platinum dish to dryness. With 
the same broken stone, again air dried, the experiment was repeated. 
1 E. S. Dana: Syst. Min., N. Y., p. 504, 1S92. 
2 G. Bischoff: Elem. Chem. & Phys. Geol. Vol. 1, pp. 57, London, 1854; 58; Vol. 2, 
pp. 116, 136, 137, 211. 1855; Vol. 3, 1859, pp. 57, 299. 
3 See J. V. Lewis, N. J. State Geol. Survey Report for 1907, p. 166. 
4 Photographed from a specimen in the collection of Mr. George E. Ashby, of New York. 
