214 Geology, &fc. of the Connecticut, 



7. Radiated Quartz, In the Southampton, Whately and 

 Leverett veins of galena ; in abundance. Also in Conway, 

 in veins and loose masses. 



8. Tabular Quartz. In greenstone, Deerfield — Lamellae 

 usually applied to one another by their broader faces, and 

 separating as thin as mica, but very brittle. Sometimes 

 they intersect and produce cells of various forms. Also in 

 Conway, in large loose masses among mica slate. Pieces 

 more than a foot in diameter have been noticed, having both 

 the structures above mentioned. The plates forming the 

 cells are sometimes covered on their broader faces with mi- 

 nute quartz crystals. In some specimens there is a gradation 

 from tabular to common amorphous quartz ; the folia becom- 

 ing less and less distinct, and finally disappearing. 



9. Granular Quartz. At Vernon, Vermont, forming a 

 bed in argillite. (J. A. Allen.) 



10. Pseudomorphous Quartz. At the Southampton lead 

 mine and in Deerfield greenstone — the impressions being 

 cubical. At the latter locality also, a very curious variety of 

 this mineral occurs. The quartz is the common limpid 

 kind; passing, however, in some parts, into chalcedony; 

 and it contains numerous cavities that diverge from a centre. 

 Their form is that of a four-sided, nearly rectangular prism, 

 generally a little flattened, and, of course, lessening to a 

 point at one end. Their length is from half an inch to four 

 inches. A complete sphere is seldom filled by them; usu- 

 ally not more than a quarter part of it; and at their outer 

 extremity they are so scattered as not to fill half the surface 

 of the sphere. 1 have sometimes observed these cavities 

 proceeding from different centres, crossing one another. 

 Although it is no uncommon thing to meet with these cavi- 

 ties, yet I have never found any mineral occupying them. 

 An interesting question then occurs ; by what were they 

 once occupied? The probability is, that it was some vari- 

 ety of zeolite. Yet no zeohte of this description has been 

 found in the greenstone in the vicinity. It exists in balls 

 perfectly filled; the crystals usually circular, and the con- 

 cretion never much larger than a musket ball. But the zeo- 

 lite, it is well known, does occur in radiated masses several 



