First the sediments were deposited, then the lithified sediments (rocks) were uplifted and folded, then an igneous intrusion cuts across the fold. Finally, erosion reveals it all for us to see.

Today, this 1,267-foot-high pinnacle of phonolite (a silica-poor fine-grained igneous rock) is described in many textbooks as an intrusion of igneous rock that never reached the surface to form a ...

News Published: 06 April 1905 British Association Geological Photographs Nature 71, 538–539 (1905) Cite this article ...