240 Rank site, a new Anhydrous Sulphato- Carbonate. 



The observed excess of soda is either due to errors of analysis, 

 as only a small quantity was used, or it may have been combined 

 with boraeic acid, as borax is very abundant at the locality. 



The interesting anomaly of a sulphate and carbonate being in 

 chemical combination reminds as of the rare sulphato-earbonate 

 of lead, Leadhillite, to which this alone bears relation as a natu- 

 ral species. 



The angles J obtained were as follows : — 



on I = 90 c . 



1 on I = 120 c . 



on 1 = 130° 30 







on 2 = 113° 30' 



Accordingly the value of the vertical axis is 1.17085. Cleavage 

 parallel to O nearly perfect, but difficult to obtain. 



Crystals striated horizontally. They are commonly terminated 

 at both ends of the prism and are very symmetrica] in shape. 

 They average, as thus far seen, about one centimeter in length 

 and thickness, with O and 1 as predominating planes (see 

 fig. 1). 



Fig. 1. 



Fig. 2. 



Sometimes the crystals are confusedly grouped (see fig. 2), 

 as from a common centre, much like the Aragonite from a 

 noted European locality. For some late years mineralogists have 

 received from several localities in the far West, groups of crystals 

 that were hexagonal (tabular) in appearance, very impure in com- 

 position, and to which, the name of Aragonite has been attached. 

 For the most part they are simply calcium carbonate mixed with 

 sand and mud, and are without cleavage. It is very probable 

 that they are pseudomorphs after the sodium sulphato-earbonate 



