. Annals of the New York Academy of Sciences. Science; Science -- New York (State). FENNER, THE WATCHUNG BASALT 155 The relations of prehnite to albite, quartz, garnet and datolite have been described. With regard to pectolite, the slides appear to present evidence that in its growth, needles of the mineral have been advanced through previously deposited prehnite, as if the latter offered no resist- ance. It will appear later that natrolite also, whose habit of growth is in similar slender needles, possesses the same property of advancing through previously existing crystals. In 87, finely fel
. Annals of the New York Academy of Sciences. Science; Science -- New York (State). FENNER, THE WATCHUNG BASALT 155 The relations of prehnite to albite, quartz, garnet and datolite have been described. With regard to pectolite, the slides appear to present evidence that in its growth, needles of the mineral have been advanced through previously deposited prehnite, as if the latter offered no resist- ance. It will appear later that natrolite also, whose habit of growth is in similar slender needles, possesses the same property of advancing through previously existing crystals. In 87, finely felted pectolite lies in contact with a spherical mass of radiating prehnite. The terminations of the prehnite crystals have lost their characteristic appearance and sharpness of outline, and the borders appear muddy. In places, the felt of pectolite is plainly advancing across the prehnite. In 76, masses of prehnite are thoroughly impregnated with pectolite needles. These cross the prelinite areas singly or in groups of three or. Fig. 21. Remnants of prehuite groups (Pr) iu stilbite (St). X 35. Slide 74. four or lie in bundles or diverging rays. The perfectly straight and sharply defined needles pierce numerous grains of prehnite without diver- sion. Similar effects, though not developed so extensively, appear in 50a and are illustrated in Plate XI, fig. 6. In this illusrtation, the straight needles near the center represent pectolite. In 93, the hand specimen shows grains of prehnite, the size of buckshot or smaller, which lie isolated in the midst of masses of pectolite. In the thin section, the prehnite appears turbid and between crossed nicols has a mottled look. Along the borders, it is difficult to decide what is pectolite and what is prehnite, though normally the two have a very different look. In 67, badly corroded prisms of prehnite are being replaced by chabazite. Fig. 21 (slide 74) illustrates the manner in which originally radiate. Please note that these images are ex
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Keywords: ., bookcentury1800, bookdecade1870, booksubjectscience, bookyear1879
