The first men to comprehend the structure of the Appalachian Mountains were the brothers, Henry D. and William B. Rogers, who from 1835 to 1842 studied them from northern New Jersey

End_Page 2161------------------------------

to southwest Virginia. They worked out the Paleozoic stratigraphy of the area and by means of it deciphered the folds of the middle Appalachians and the thrust faults of the southern Appalachians. They attempted to explain the structure as the result of great explosions on the southeast but, beginning with Dana, geologists have come to ascribe the structure to lateral compression.

Since the time of the Rogers brothers, many structural ideas have emerged from the study of the Appalachians, such as the geosyncline, underthrusting, erosion thrusts, the competence of strata. Prominent among the many investigators was the group of geologists headed by Willis and Hayes who, late in the nineteenth century, worked out several of the low-angle large-displacement thrust faults of the southern Appalachians and attempted to explain the mechanics of Appalachian structure.

In recent years there have been developing two schools of thought on the depth of Appalachian deformation. One school holds that all large folds and faults extend down to and are supported by the basement; the other holds that the deformed rocks have been stripped completely off the basement along one or more great bedding-plane thrust faults.

End_of_Article - Last_Page 2162------------