OTHER ZEALITES 473 



deposition is not clear, but it resembles t}^pe II more closely than any- 

 other. 



CALCITE AND ABAGONITE 



Calcite is only occasionally present in scalenohedral crystals. Its 

 position appears to lie between thomsonite, type III, and mesolite. 

 Aragonite is more commonly present. It is the very latest mineral de- 

 posited, and occurs in thin transparent or whitish coatings on most of 

 the younger minerals. 



Order of Deposition 



The minerals here described, as well as their different varieties, occur 

 so frequently associated together that, for most of them, the order of 

 deposition is ver}? readily observed. For the purpose of ready compar- 

 ison, the order as determined in the new locality and that given by Cross 

 and Hillebrand are placed in parallel columns. 



Order of deposition in new locality. Order of deposition observed by Cross and 



Hillebrand. 



1. Laumontite. 1. Laumontite. 



2. Stilbite. 2. Stilbite. 



3. Chabazite. 3. Thomsonite. 



4. Thomsonite, type I. 4. Calcite (yellow). 



5. Apophyllite. 5. Stilbite. 



6. Thomsonite, types II and Ila. 6. Chabazite. 



7. Laumontite. 7. Thomsonite. 



8. Stilbite. 8. Analeite. 



9. Analeite. 9. Apophyllite. 



10. Thomsonite, type III. 10. Calcite (colorless). 



11. Calcite. 11. Mesolite. 



12. Thomsonite, type Ilia. 



13. Mesolite. 



14. Analeite. 



15. Aragonite. 



The differences between the two will be seen to be very slight, and can 

 mostly be accounted for by the recognition of a second period of laumon- 

 tite deposition and of the different stages of thomsonite formation. 



Summary 



In a newly opened quarry on the east face of North Table mountain 

 at Golden, Colorado, are found a great variety of zeolites of which thom- 

 sonite, mesolite, and chabazite are the most important. These occur 

 sometimes separately, filling or lining adjacent cavities, but more often 



