The subject of Appalachian structure is one of the most interesting in geology in that it affords the greatest example of mountain structure in the world. All stages of deformation from undisturbed rocks to beds folded, overturned, broken, mashed, and metamorphosed are seen throughout the entire length of the system, 2,000 miles from Alabama to Newfoundland. The connecting links between the types of structure are finely exposed and the chain is complete. The rocks exposed range from earliest Precambrian to Tertiary, and the depths of the earth are laid bare in the heart of the range in a manner nowhere equaled.
The beginning of the study of the Appalachians practically coincides with the beginning of American geology about 100 years ago. The principal structures of the folded sediments were made known by the work of the Rogers brothers in Pennsylvania and Virginia about 80 years ago. Substantial contributions were . . .