122 TRANSACTIONS OF THE [JAN. 20, 
Heat from crushing and folding did not produce the meta- 
morphosis. The slickensided coal of the White Ash mine has 
almost 40 percent. of volatile; the ‘‘ Coking seam” in the upper 
part of Coal cafion is decidedly bituminous, though the White 
Ash, higher up the hill is an almost graphitoid anthracite. 
The facts appear to point to but one conclusion—that the 
coal was changed into anthracite solely by contact of the beds 
with the enormous mass of eruptives. 
Nore.—The specimens of eruptive rock obtained near Madrid 
were submitted to Prof. J. F. Kemp, who has furnished the fol- 
lowing results of his examination. 
1. Mesa, Coal Cation. Markedly porphyritic rock. Pheno- 
crysts, orthoclase in excess, plagioclase much rarer ; hornblende 
abundant, augite much rarer. The groundmass is both finely 
crystalline and glassy. The orthoclase phenocrysts are zonal, 
and generally of six-sided cross-section with extinction parallel 
to one of the sides. The rock is a trachyte and has the texture 
of a surface flow. 
2. Dike near Boyle’s Mine, Coal canon.—Markedly por- 
phyritic. Phenocrysts of orthoclase and plagioclase, former in 
excess; hornblende abundant, augite much rarer; occasional 
quartz. Some small shreds of augite and hornblende; magnetite 
and titanite. The rock is a trachyte and has a texture not dif- 
fering essentially from a surface flow. 
3. Mesa above White Ash Mine.—Markedly porphyritie. 
Phenocrysts of both orthoclase and plagioclase, but both show 
strains and undulatory extinctions. Much green hornblende, 
comparatively little augite, titanite, magnetite; finely crystalline 
groundmass containing some glass. The rock is a trachyte and 
has the texture of a surface flow. 
4. Dike below the White Ash Mine.—Porphyritic structure 
poorly, if at all developed. The rock is holocrystalline. The 
feldspars are much the most abundant minerals and orthoclase 
is more common than plagioclase. Augite is abundant in well 
bounded crystals and surpasses hornblende in amount, Par- 
allel growths of the two occur. Magnetite and titanite are 
present. The rock is a dike or deeper seated phase of the others 
and to this owes its tendency to a granitoid structure. 
T should think that all four specimens were derived from the 
same igneous magma and eruption, and that the mineralogical 
variations and the difference between the texture of the last and 
those of the others were not suflicient to make them worthy of 
different names. They are all trachytes with close affinities 
for andesites. No. 3 in particular is strongly andesitiec. 
