This investigation was undertaken primarily as a pilot‐experiment for gaining information concerning the field‐technique and accuracy which is needed for covering large areas in detail and at the same time economically. Owing to the complex nature of magnetic observations, such a pilot‐study serves, in addition, as a basis for determining the best methods of presenting the results of large areal studies in an easily comprehensible form. The State of Florida was chosen for such preliminary study for the following reasons: First, because it is geologically ideal for such an investigation since it comprises a series of unconsolidated, flat‐lying, Tertiary and Cretaceous sediments of low magnetic permeability covering a complex and much‐folded crystalline basement composed largely of rocks carrying strongly paramagnetic materials; secondly, because information concerning the structural trends of the crystalline basement would be of great interest and importance in the study of Appalachian orogeny and the relationship of the Florida Peninsula to both the Appalachian and Antillean tectonic systems.
