134 Cross and Ilillebraiol—Miw rah in the basalt of 



None of the mesolite needles are large enough to allow any 

 determination of their crystal form, even under the microscope 

 at a high power. They seem simply like very fine transparent 

 hairs. The identification as mesolite, rests 'therefore, on the 

 following chemical analysis : 



If mesolite be considered as a mixture of the isomorplicus 

 silicates contained in scolecite (CaAl 2 Si 3 O 10 +3 aq) and natrolite 

 (Ni . A ' (Si 8 O 10 +2 aq), the present occurrence would answer very 

 nearly to the requirements of the combination of 2 of scolecite 

 + 1 of natrolite, the percentages of which would be Si0 2 

 46-32, A1A 26-40, CaO 9-61, Na 2 5-32, H 2 12-35 =100-00. 



With mesolite ends the chief M-ri.-s of Table Mountain 

 zeolites. The species described are for the most part clear or 

 colorless, and well defined in crystallization, while they occur 

 so often associated as to make the order in which they have 

 been described a perfectly natural one. 



A second series of zeolitic minerals will now be taken up, the 

 members of which, in time and manner of deposition, and par- 

 tially also in composition, are very distinct from those already 

 mentioned. 



In the previous article (this Journal, June) chabazite was 

 stated to be " the oldest of the zeolites, with the exception of 

 certain peculiar stratified deposits in some of the cavities." 

 deposits has been determined, 

 nation of minerals discovered, 

 observer in the zeolitic zone of Table 

 Mountain is immediately attracts] h> a reddish-yellow sand- 

 stone-like material, which occurs in many of the cavities. In 

 the larger ones it takes the form of a floor, the upper surface 

 being horizontal, and the deposit may be several inches in 

 thickness. Small cavities have been completely filled by it, 

 and it is clear that the deposition has taken place from the 

 bottom of each cavity, upward. 



In parts of South 1 specially, the same ma- 



terial has filled fissures. Usually the lower portic 



grains, 



