58 



GEOLOGY OF THE SECOND DISTRICT. 



The minerals which are the most difficuU to fuse, are the ones which exliibit this softened 

 aspect ; while the feldspar, spiiene, scapolite, pyroxene and tourmaline present forms tolerably 

 perfect. Zircon, which is quite common, and is the most perfect, seems to be an exception to 

 this statement ; its edges are always finely formed, sharp, and perfect. 



Another fact quite common, and equally interesting with the preceding, is found in the 

 fractures and flexures of the crystals. They are finely seen in the long prismatic crystals of 

 zircon and phosphate of lime. The annexed figure is a representation of a bent crystal of 

 piiosphate of lime. 



Tint this substance should be capable of bending, requires a support on all sides, or else 

 that the force should be applied while in a softened state. The surface exposed in the fissures 

 lo k as if they were torn from each other ; which favors the state I have supposed the crys- 

 tal might have been in at the time of its injury. But it is quite common to see the crystals 

 of lime fractured directly, and one portion removed beyond the axis of the other. In fact, 

 very few of the larger crystals of the locality at Rossie, but have been broken, many of which 

 are mended by a ihin layer of carbonate of lime. The imperfections of the larger crystals 

 are to be attributed to the fracture they have suffered, and to the numerous imperfections in 

 the interior which I have already noticed. 



Most of the large crystals of zircon are either broken or bent. Figure 18 is an example of 

 this kind. 



Of the fact of a fracture, there can be no doubt, when we examine the ends or the surfaces 

 of the broken fragments ; for we shall find them to fit or match with precision, and might be 



