346 Spodumene and its Alterations. 



prism), on the one side of it appear the rigid fibres of Killinite, 

 straight and parallel, and, on the other, end to end, the curved 

 needles and blades of the more flexible Cymatolite. But along 

 that portion of the line, at the sides of the prism, where it runs 

 parallel to the fibres of Spodumene or Killinite, it displays 

 minute but abundant rounded indentations into the mass of the 

 latter minerals, now occupied by the ends of Cymatolite-needles, 

 in projecting bundles, or sometimes mixed in great disorder. 



These indentations are also represented in the drawing (Fig. 

 2, Plate XIII): K — k is the Killinite, retaining the fibrous tex- 

 ture of the original Spodumene, c is the Cymatolite, and 

 a — a the irregular line of contact between the two minerals. 

 Along this line, many of the blades of Cymatolite display their 

 terminations still perfect, being more recently formed and as 

 yet sheltered from the pressure. The ends of many others are 

 broken off bluntly or more or less obliquely, and the fragments 

 appear here and there along the contact-line and even in the 

 Killinite, as at b; while several blades have been crushed up 

 into a mass of irregular scales, at c, by a side-thrust from the 

 left. The dark points scattered about are particles of ferric 

 hydrate. The drawing was made under the microscope, and 

 with the help of the camera lucida, upon a thin cross-section 

 of an altered crystal, and at a magnifying power of 1002 di- 

 ameters, (reduced to 617 at the size of the wood-cut). * 



III. 

 Albitic Granite aftek Spodumejste. 



The pseudomorphs most conspicuous by size, even more so 

 than those of Cymatolite, consist ot a vein-granite, made up 

 of Muscovite, Albite, and Quartz, in varying proportions, even 

 within the same pseudomorpb, with Manganese-Garnet, Oersted- 

 ite, Beryl, etc., occasionally interspersed. 



The large Cymatolite-columns genprally pass at one end into 

 mixtures of this character, and enormous masses of one or two 

 hundred weight have thus been formed. They consist of an aggre- 

 gation of jierhaps only two or three pseudomorphs of this kind, 

 rudely but in places distinctly shaped, each from several inches 

 to nearly a foot in diameter, and from one to nearly three feet 



