ELISIIA MITCHELL SCIENTIFIC SOCIETY. 77 



If this specimen was slightly heated (the mere heat of the 

 hand was found sufficient) the bubbles would grow gradually 

 less until they disa[)peared entirely, and the fluids would unite. 



On cooling, a critical temperature would be reached, when all 

 the cavities woidd be filled with uumbei'less minute bubbles, 

 which, rushiug together, would in a few seconds form to its full 

 size the bubble originally noticed. I found that this experiment 

 could be repeated indefinitely, without any diminution of its 

 interesting phenomena or risk of damage to the specimen. 



To Alexander county, North Carolina, and to many of the 

 surrounding couutie>, we can hereafter look to produce fluid- 

 bearing quartz crystals second in interest to those of no other 

 reunion in the world. 



False Pseudomorphs of Quartz. — In the older works 

 on mineralogy mention is made of '^pseudomorphs of quartz 

 after barite," " pseudomorphs of quartz after calcite," and 

 of pseudomorphoiis quartz," as occurring in Rutherford county, 

 N. C. In all the mineral collections where the writer has seen 

 specimens from this locality, they have been found labeled as 

 above noted. 



Opinions seem to have been divided between the identity of 

 these forms with barite and calcite, though I have often heard 

 them stated as representing the form of "an unknown species." 



The specimens are conspicuous for their ever varying and 

 unsymmetrical forms, their inconstant angles, and for being 

 almost invaribly hollow, like geodes. The best speciruens from 

 Rutherford county, N. C, were found by Col. Twitty previous 

 to 1870, and as early as 1850 the locality was well known. It 

 had a local fame based upon the not unfrequent discovery of 

 'Svater- bearing crystals" among the irregular quartz masses, 

 which had a ready sale and were the cause of whatever develop- 

 ment the locality ever received. 



A second locality is situated in Iredell county, near Statesville, 



on the land of a Mr. Crawford. It is noted for the abundance of 



the material there occurring, the large size of the separable 



masses, the almost solid character of the forms and the uon- 



5 



