330 GEOLOGY OF OLD HAMPSHIRE COUNTY. 3JASS. 



alkalies. Immediately afterwards Brush and Daua proved the cymatolite 

 to be a mixture of albite aud musco'V'ite formed fi'om the spodumene with 

 the intervention of a litliia- nepheline (eueryptite), and made it probable 

 that the killinite was mainly hydrated muscoA"ite, and thus the series of 

 pseudomorphs is reduced to one type, namely, spodumene changed to 

 albitic granite, whereby, from the gradual suppression of any one or two of 

 the constituents, forms paade up of either quartz, mica, albite, or mica and 

 albite result. Pseudomorphs a yard in length and nearly a foot across are 

 made up of a coarse mixtm'e in various proportions of albite, musco'vite, 

 and quartz, with manganese, garnet, zircon, beryl, etc., occasionally inter- 

 posed, aud we niav add also microcline. 



ORDINARY METEORIC ALTERATION. 



By ordinary carbonated waters there has been a gradual removal of a part of the 

 lithia aud more soluble protoxides, almost universal, with the cou.sequent eftect upon 

 the physical characteristics of the mineral shown by the loss of weight, luster, greenish 

 color, and trauslucency. 



The zircons have absorbed water and lost part of their uranium, which has sep- 

 arated as autunite, torbernite, and, by a further decomposition, uranocher. The 

 garnets aiford oeher and pyrolu.site in dendritic films. 



The triphylite by absorption of water and higher oxidation of some constituents 

 has assumed its present altered form, so that only rarely do small blue nuclei of the 

 unaltered mineral remain. 



The spodumene and cymatolite both at last degenerate into clayey material, 

 sometimes pink and allied to kaolin or montmorrillonite.' 



The kaolin beds at Blandford village illustrate on a large scale the 

 results of the agencies described in the last section. Great beds of coarse 

 gi'anite in everv stage of alteration are exposed in the diggings; in some 

 parts the feldspars are oulv softened and made friable, in others they are 

 pure soft kaolin, and the mica-schist which is tangled among the big veins 

 is rotted to a soft, rusty earth. All the fissures in the altered mass are 

 blackened by deposits of manganese oxide. It is quite certain that this 

 deep-seated alteration of the granite is mainly pre-Glacial and owes its 

 preservation to its position on the southeastern slope of the hill upon whicli 

 the village is built. The material has been used extensively at Russell for 

 the manufacture of brick of fine quality and tile, but recently the buildings 

 have been destroyed by fire. 



' A. A. Jnlien, Spodumene and its alter.itions : Annals X. Y. Acad. Sci., Vol. I. p. 353. 



