ABSTRACT A local clay lens up to 60 cm thick in the Eocene Castle Hayne Limestone at the abandoned Fussell Quarry, Duplin County, North Carolina, is identified as a bentonite. It is composed of authigenic smectite with sparse euhedral biotite and apatite. Scanning electron microscope examination shows that the bentonite consists of relic bubble-wall shards altered to smectite. Smectitic columnules, rod-shaped casts of elongate pipe vesicles in pumice fragments derived from early dissolution of nearby small glass shards, also occur. This association is considered diagnostic of a silicic air-fall ash. K-Ar and Rb-Sr biotite dates from the bentonite are 46.2 ± 1.8 Ma and 45.7 ± 0.7 Ma, respectively, and a fission-track age of apatite is 51.0 ± 2.0 Ma; this later date is considered to be incorrect. Biotite compositions determined from electron microprobe analyses on 100 crystals suggest derivation from a single volcanic source no more than 4000 km from the bentonite. Possible sources of the ash include Bermuda; Highland County, Virginia; and the Caribbean; however, because of distance, prevailing wind direction, and similarity in age and composition, the volcanic swarm in Highland County, Virginia, is the suggested source.

Abstract The Martin Marietta Aggregates Ideal Cement quarry at Castle Hayne is located approximately 2 miles west of the intersection of U. S. 117 and State Road 1002 on the north side of State Road 1002, in the Castle Hayne 7.5-minute quadrangle. The quarry exposes the Rocky Point Member of the Peedee Formation, and Sequences 1, 2, 3 and 4 of the Castle Hayne Limestone.

Abstract There have been numerous conflicting interpretations of the stratigraphy and age of the Castle Hayne Limestone since it was first formally described by Miller (1912). Recent interest in these Eocene carbonates was precipitated by nearly simultaneous, but very different stratigraphic revisions proposed by Baum et al. (1978c) and Ward et al. (1978) (Figure 1). Subsequent studies by Baum et al. (1979), Worsley and Turco (1979), Zullo and Baum (1979, 1980), Harris and Zullo (1980), Kier (1980), Ward and Blackwelder (1980), Baum (1981), Otte (1981), Jones (1983), Berggren and Aubry (1984), Hazel et al. (1984), Zullo (1984), and Harris et al. (1984) addressed more specific issues of paleontology, biostratigraphy, ehronostratigraphy, and petrology, and some were directed toward a substantiation of one of the 1978 stratigraphic revisions. Kier (1980) in his monograph of Eocene echinoids of the Carolinas, provided the first indication that neither of the 1978 stratigraphic revisions truly reflected the lithostratigraphic complexities encompassed by the varied carbonate facies grouped in the Castle Hayne Limestone. Kier established a sequence of three Informal assemblage zones (”early,” ”middle” and ”late”) that strongly suggested that the assignment of Eocene carbonates to either the scheme of Ward et al. (1978) or Baum et al. (1980) was in error. Although the significance of Kier’s new data was initially recognized by Baum et al. (1979), and is partially reflected in the correlation chart proposed by Harris and Zullo (1980), it has only been through the application of sequence-stratigraphic concepts to the Castle Hayne that a coherent stratigraphic

Abstract Westward expansion of the Fussell Ouarry (see Fig. 5 of Road Log for location) has exposed a dark-gray clay lens in Castle Hayne Limestone. The clay is composed mainly of smectite, and by currrently accepted usage (Grim and Guven, 1978) can be termed bentonlte. This paper reports a geochemical, mineralogical and petrographical study of the bentonite and demonstrates its derivation from volcanogenic sediment. Bentonite samples were studied by a variety of techniques, including: X-ray radiography; X-ray diffraction (XRD); scanning electron microscopy (SEM) with an energy dispersive X-ray analyzer (EDX); chemical analyses by X-ray fluorescence (XRF) and wet chemistry; and petrographic modal analyses of smear slides, thin sections and grain mounts.