ELISHA MITCHELL SCIENTIFIC SOCIETY. 37 



the grains fittinof perfectly into each other without in- 

 terstitial spaces or cementino" material. 



(9) The mineralogfical varieties pass irregularly into 

 each other without interlamination or any regularity of 

 structure whatever. They present typical mag-matic 

 differentiation. 



(10) The perfectl}^ fresh condition of the olivine, a 

 mineral so prone to alteration, is incompatible with any 

 theory of sedimentation with subsequent solidification, 

 metamorphism and erosion. 



Chapel Hill, N. C, 

 Feb 1, 1896. 



EXPLANATION OF PLATE V. 



Fig. I. Specimen from railroad cut 2 miles west of Balsam Gap, 

 fackson^ Co., N. C. 



This is an exceptionally fresh specimen of the pure olivine type. 

 Crystal outlines are rather more common in this section than usual. 



Fig. 2. Specimen from Carter Corundum Mine ^ Madison Co., N. C. 



This fig-ure represents the prevailing- character of the surface ex- 

 posures of dunite. The first narrow bands of yellowish g-reen ser- 

 pentine, which afterwards constitute the ' mesh-structure' have just 

 been formed. 



Fig. J. Specitnenfrojn Carter Corundum Mine, Madison Co., N- C. 



This section shows a common type of fine g-rained dunite. It is 

 here seen between crossed nicols, and the extinction tog-ether of the 

 fine g-rains over considerable areas shows that it is essentially a 

 coarse-g^rained rock, like that shown in Fig-. 1. 



Fig. 4. Specimen from Webster, Jackson Co., N. C. 



This specimen shows an advanced stage in serpentinization, the 

 beg-inning of which is shown in fig-ure 2. Rejected iron oxides have 

 been deposited in dark bands about the olivine remnants. 



Fig. S' Specimen prom Paint Fork, Madison Co., N. C. 



No olivine fragments are found in this specimen. Except for the 

 black accumulations of iron oxides, the rock looks homog-eneous in 

 ordinary lig-ht. 



Fig. 6. Specimen the same as for Fig. 5. 



This fig-ure is identical with the last, except that it is here seen 

 between crossed nicols. The luesh-structure' outlining- the origi- 

 nal olivine grains is well shown. (The view is inverted with refer- 

 ence to fig-ure 5.) 



