130 



tion of the matrix of the crystal during the time of its formation. In- 

 dividuals exhibiting this peculiarity, are not uncommon, and in some 

 the number of these so called planes, is still further increased. 



Since the publication of the Mineralogy of New-York, I have re- 

 ceived sundry specimens of quartz crystals from St. Johnsville, in 

 Montgomery county, collected by Mr. Israel Smith, Jr. One of these 

 is similar to fig. 156, from Middleville, but with the planes, z and % 



more extended. Also No. 161, of the Mineralogy, and several other 

 more common forms, but the crystals are usually quite small. 



To the figures of crystals heretofore found in the town of Edwards, 

 St. Lawrence county, I have to add the one now introduced, which 

 occurs in a group of dodecahedrons, for which that locality is so remark" 



able. It is the same form as that from Ulster county, fig. 172, of my 

 Mineralogy. Some of these crystals have blades of specular iron 



