Cover. (a) Filtered gravity map of the 48 contiguous states. Produced by Hildenbrand, Simpson, Godsen, and Kane as USGS Map GP-953(A). (b) The map cut and recorrelated. Gravity signatures of the following major features are aligned. (1) Central North American Rift System, Hartville Uplift; (2) Precambrian/Early Paleozoic Rift Passive Margin underneath the Appalachians, Precambrian/Early Paleozoic Rift Passive Margin underneath the Quachitas. Though this offset was independently recognized by the author, it is similar to that proposed by S. W. Carey (The Expanding Earth, Dev. in Geotonics, vol. 10, pp. 378–380, Elsevier, New York, 1976). These alignments are interpreted to indicate that a strike-slip fault system (transform fault?) offset these features probably concurrent with rift passive margin formation leaving the Palezoic Iapetian Eastern-Southern continental margin bounded as follows: rift passive margin—transform passive margin—rift passive margin. Late Palezoic continental collision resulted in major overthrusting of the margin forming the Appalachians; lesser overthrusting, because of relatively recessed position, forming the Quachita's and minor thrusting with considerable shearing, because of the orientation of the transform boundary with respect to the closing vector, forming the buried Appalachian-Quachita connection in Mississippi and Alabama (G. L. Kinsland, Transcontinental strike-slip fault across North America, paper presented at the 5th International Conference on Basement Tectonics, Oct. 1983). Features south and east of the rift passive margins were not in place at the time faulting occurred and would not a priori be expected to correlate in (b). The small features which do correlate in (b) from north Louisiana northeast along the Atlantic coast are believed to be signatures of portions of collapsed Late Palezoic island arc complexes which correlate due to similar structural relationships to the rift passive margins. Florida does not correlate with southern Mississippi and Louisiana. At this time, no reason for extending the cut through Florida other than necessity to illustrate the other correlations is given. A signature similar to the rift passive margin signatures is noted in southern Mississippi, southern Louisiana, and coastal Texas and is interpreted as the Mesozoic Gulf Coast rift passive margin signature (G. L. Kinsland, Basement Structure of the Gulf Coast: Interpretation of gravity anmalies supported with structural, magnetic and seismic data, Trans. Gulf Coast Assoc. Geol. Soc, in press, 1984).