264 Descriptive Catalogue of Rocks and Minerals. 



11. The same of an inferior quality, fibrous. 



73. Slaty and fibrous mass, found in detached pieces 

 among the plumbago. 



74. Hornstone passing into flint, found in nodules, often 

 four inches in diameter, near this village. 



75. White Marble from Hagerstown, Maryland, resem- 

 bling the statuary marble of Vermont. 



76—7. Foliated Talc from Stokes. 



78. Fibrous Gypsum, Western part of N. C. 



79. Agate, from Stokes. 



80 — 7. Specimens designed to illustrate the Plumbago 

 formation of Wake County, viz. 



80. Close grained slaty of the best quality. 



81. Friable when dug from the pit, but hardens on dry- 

 ing. 



82. Same as 80 with a vein of Tremolite. This fre- 

 quently appears between two contiguous layers of slate, and 

 sometimes in detached pieces as in 73. 



83. Rock that forms the bed of the plumbago, taken 

 from the walls. 



84. Micaceous Rock that accompanies the Plumbago, 

 same as 83, freed from the Plumbago. This rock has been 

 described in No. 22. It is most commonly red, but some- 

 times as in the next specimen. 



85. White Micaceous rock, associated with Nos. 84 

 and 87. 



86. Micaceous Sandstone, occurs on the western side of 

 No. 84, between that and the great sandstone formation, 

 much valued for whetstones and grindstones for softer in- 

 struments. No. 18 is a variety of the same. 



87. Yellow Micaceous Rocks, associated with Nos. 84 

 and 85. 



Of this immense formation of Plumbago,* 1 propose to 

 furnish a more particular account, and also of a number of 

 other articles comprised in these notes. 



* Appearing, as I am credibly informed, fifteen miles from N. to S. and in 

 some places three fourths of a mile in breadth. 



