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MINERALOGY AND GEOLOGY. 



Minerals are found either in regular and geome- 

 trical forms, which bear the name of crystals, or 

 in masses more or less irregular. Amongst the 

 crystals, there are some so situated, that we can, 

 without injury, separate them from their support 

 or the substance which surrounds them. Others 

 compose groupes projecting beyond their support, 

 and others appear buried in cavities in the interior. 

 We must procure, as frequently as possible, the 

 specimens in these three states* As regards the 

 crystals inserted within the surrounding substance, 

 we detach parts of this substance with them, at 

 least from three to four inches large in every sense, 

 so that we may observe the different minerals which 

 accompany the crystals. We also detach portions 

 of the masses composed of needles, fibres, of the 

 granulous or compact, taking care to choose them 

 in a state of freshness, and free from alteration, 

 which is most obvious in those situated near the 

 surface. 



In collecting fragments or specimens of rocks, 

 minerals, volcanic products, or fossile organised 

 bodies, it is most essential to note their stratifica- 

 tion well ; that is to say, the nature of the place in 

 which they are found, and their relative position 

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