Walcott — Occurrence of Olenellus in New Jersey. 309 



perhaps more easily produced. It was moreover observed that 

 milky, white crystals yielded the basal cleavage more readily 

 than clear, transparent ones. If the crystals are broken with- 

 out care they usually show only an irregular to conchoidal 

 fracture. The same holds true for the transparent crystals 

 from Franklin, while the ordinary massive specimens usually 

 present only irregular fractures. A good prismatic cleavage, 

 which may occasionally be observed, is perhaps of secondary 

 origin, resulting from pressure. All attempts to produce 

 cleavages on the crystals from Salida and the Merritt mine 

 failed, owing to their shape and small size. 



In conclusion, therefore, the author believes that there are 

 no essential differences in cleavage or crystallization between 

 willemite and troostite which warrants their separation into 

 distinct species. 



Laboratory of Mineralogy and Petrography, 

 Sheffield Scientific School, November, 1893. 



Art. XXXI. — On the Occurrence of Olenellus in the Green 

 Pond Mountain Series of Northern, New Jersey, with a 

 Note on the Conglomerates ; by Charles D. Walcott. 



In company with Dr. John C. Smock, State Geologist of 

 New Jersey, I visited, in October, 1893, several localities of 

 the Green Pond Mountain rocks in northern New Jersey, and 

 also crossed into Orange County, New York, to see the section 

 of the southwestern portion of Skunnemunk Mountain. 



The first locality that we examined was at a point four miles 

 northeast of Newfoundland and two miles north of Lake 

 Macopin, where the succession from below upward is, gneiss, 

 bedded quartzite, massive-bedded siliceous limestone, and a 

 belt of shales that pass beneath the conglomerate of Kanouse 

 Mountain. The latter formation extends to the southwest and 

 merges into the Copperas Mountain conglomerate. Fragments 

 of Olenellus were found in the limestone. Subsequently I 

 visited the Gould quarry, one mile north of Macopin Lake, 

 where the section is essentially the same, but more complete.* 

 The quartzites are separated by a slight interval of soil from 

 the gneiss, and pass above into a conglomerate formed of 

 white quartz pebbles in a reddish matrix. Reddish-purple 

 sandstones also occur associated with the conglomerate, the 

 whole forming a mass not over ten feet in thickness. The 

 superjacent limestone has been extensively cut into in quarry- 



*Geol. Surv. New Jersey, Ann. Rept. 1884, p. 52. 



Aji. Joue. Sci— Third Series, Vol. XLVII, No. 280.— April, 1894. 

 21 



