We document nine lower-middle Eocene sequences on the New Jersey coastal plain and compare them with global δ18O and Haq et al. records. Early Eocene hiatuses do not match δ18O changes, and it is unlikely that they are the result of glacioeustasy, consistent with an ice-free early Eocene. Early-middle Eocene (49–43 Ma) evidence for a link between sequences and δ18O is equivocal, and the presence of large ice sheets is uncertain. Beginning in the late-middle Eocene (43–42 Ma), concomitant increases in planktonic and benthic δ18O records coincide with the timing of hiatuses on the New Jersey coastal plain and a change from carbonate-dominated to siliciclastic-dominated sedimentation. These represent the development of the Antarctic ice cap and the beginning of the “icehouse” world. Of the 14 sequences predicted by Haq et al. for this interval, 9 are resolvable on the New Jersey margin, and the other 5 appear to be combined with others. We conclude that although ice-volume changes controlled sequences since at least 42 Ma, mechanisms for sea-level change prior to then are still not fully understood.