A 



364 



DESCRIPTIVE MINERALOGY. 



Fig. 157. 



Fig. 158. 



Fig. 159. 



Fig. 160; 



Fig. 161. 



Fig. 152. P on a 145° 22' ; cona 159° SCK ; c on P 165° 30' ; z" on a 11 1° 15' ; z on o 

 137° 51' ; z on e 145° 30' ; a on e 175° 30' {Shepard). 



Figs. 157, 158, 159, 160. P on a 145° 22' ; Pont 154° ; P" on t 103° 50' ; t on z 155° ; 

 r on t 133° 50' ; z on a 137° 51'; P on c 165° ; e on z 145° (Horton). 



Fis. :C1 (bis). 



A 



^ 



Fig. 162 



Jefferson County. On the banks of Vrooman lake, in the 

 vicinity of the village of Oxbow, crystallized quartz is found 

 in cavities and geodes, associated with crystallized calcareous 

 spar. The crystals are small, usually regular six-sided prisms 

 with six-sided pyramids. These sometimes cross each other 

 at right angles, as in the accompanying Fig. 161 {bis). They 

 are translucent and transparent, and occasionally have a yel- 

 lowish tint. 



In the same town (Antwerp), at the Sterling ore bed, crys- 

 tallized quartz is associated with the specular iron, and is often 

 coated with the rare Cacoxenite. These crystals, which are usually 

 limpid, but are occasionally tinged by oxide of iron, have the prisms 

 very short, as in Fig. 144 ; or entirely wanting, forming the dodecaedre 

 of Haiiy, Fig. 162. They are similar to those which occur in St- 

 Lawrence county, but are smaller. 



It is a curious fact, that the cavities in which these crystals occur, 

 often contain pure water or a colourless liquid. The same thing, how- 

 ever, has been observed in regard to geodes of quartz and other crystals 

 at various localities, both American and foreign.* 



See Brewster^s Edinburgh Journal of Science. X. 24 and 28. 



I 



