A boulder of Roan Mountain gneiss

Figure 5. This boulder was quarried from the mountainside. (Photograph by Dirk Frankenberg. More about the photograph)

Figure 5 shows a boulder of Roan Mountain gneiss quarried out of the mountainside and doing duty now as a persuasive “No Entry” signal to those thinking of using an off-limits Forest Service road. The bands of quartz show up nicely in this recently exposed surface. Note however that the orientation of the quartz layers are at right angles to those in Figure 4. The Figure 4 orientation is the natural one, and observers should interpret the current vertical orientation of quartz layers as evidence of the huge forces brought to bear on these rocks when continents collided and mountains formed.

next