Table Mount" n<, h <:■,/,- <?nhln, Colw*ado. 



There is no calcite in the product at all. The substai 

 light, has a pearly luster, and is finely foliated parallel t 



basal plane of the apophyllite. The' alteration proceeds 

 without. Farther data concerning the substance and tin 



In the form of wine-yellow crystals, it preceded even chaba- 

 zite, being in all observed cases deposited directly on the basalt, 

 and coated usually by chabazite or thomsonite. 



It is rarely found in those cavities to which water has had 

 access through fissures, having been dissolved. 



The second deposit of calcite cam..' after apophyllite. These 

 •crystals are colorless or slightly straw-yellow, and the form of 

 both varieties is commonly that of a sharp scalenohedron ter- 

 minated by a low rhombohedron. 



The aragonite is present only as a snow-white incrustation, 

 appaivntly'with a special tendency to deposition upon chaba- 

 zite, though often noticed on apophyllite and thomsonite. It 

 was next to the last mineral deposited, only mesolite having 

 been observed upon it. 



6. Mesolite. 



Mesolite is the last of the minerals deposited at the k>ea!it\ 

 on North Table Mountain, where all of the species thus far 

 described occur so often together, that their order of succes- 

 sion is plain (this Journal, dune). The mineral appears uni- 

 formly in masses composed of exceedingly delicate needles, 

 loosely grouped together, very much like the spicules of a fine 

 sponge. £■/ ■ ne'pienrh- fill the smaller cav- 



ities entirely. In the larger ones, the bases of the rounded 

 bunches, 1 to 2 inches in diameter, often touch each other. 

 The very latest deposition, the finishing touch so to speak, is a 

 thin film, coating the whole mass. This is sometimes a con- 

 tinuous membrane, and in other cases more like a thick cob- 

 web. The exquisite delicacy of some of these films is quite 

 wonderful. In rare cases, bunches on the upper and lower 

 walls of a cavity are united by such a membrane. Single 

 needles are clear, but ars pure white. 



As was mentioned under thomsonite, the loose aggregates of 

 the second generation of that mineral, seem specially suited to 

 attract the deposition of mesolite. 



