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University of California. 



[Vol. i. 



bundle of slightly divergent rods into which the lateral club-like 

 bodies pass. These vermicular rods sometimes overlap and cross 

 one another, but never intersect. Different rods may be seen one 

 above the other in the thickness of the slide. They frequently 

 branch from a common stem. These rods are composed of cloudy 

 nepheline, and in the ordinary preparations the structure is difficult 

 to study. If, however, the slide be treated with dilute hydrochloric 

 acid and stained with fuchsine, the nepheline rods are very sharply 

 marked off from the orthoclase with which they are intergrown, 

 the rods being colored, and the orthoclase colorless. The ortho- 

 clase extinguishes sharply as a unit in common with that beyond 

 the area of intergrowth. Figure 2 illustrates the morphology of 

 the intergrowth, which seems to be very similar to an intergrowth 

 of the same minerals in the rock borolanite described by Teall.* 



Figure 2. — Intergrowths of orthoclase and nepheline in nepheline-pyroxene- 

 malignite. The shaded parts are nepheline and the clear ortho- 

 clase. 



The apatite is remarkable for its abundance, and for the size of 

 its crystals. It occurs in stout prisms having a maximum length 

 of about 3 mm. These are very striking features of the slides, and 

 the mineral can not be regarded as playing a merely accessory role. 

 The crystals are all perfectly fresh and water clear, but exhibit quite 

 a marked relief, and a very notable total reflection of the light on 

 the borders and along the cracks, the presence of the latter being a 



*Trans. Ro\ai Soc, Edin. Vol. XXXVII, Pt. 1, No. 11, 1892. 



