Stratigraphy and duration of the extrusive interval in the Newark basin based on cores. Because the Interbedded sedimentary units are highly cyclical, we can count the number of cycles to estimate the duration of the extrusive interval to ~620,000 years. This includes ~10,000 years for the eruption of the Orange Mountain Basalt and ~60,000 years. These results differ slightly from those determined previously. The modeled precession curve used here provided a better match with the cycles than the curve used in the initial 1996 attempt. Recent high-precision U-Pb isotopic dating indicate that the age of the oldest flow is ~201.5 Ma and the age of the youngest flow is ~200.9 Ma (e.g., Blackburn et al., 2013), with a difference of ~605,000 years. Modified from Olsen et al. (2016) based on Whiteside et al. (2007), Olsen et al. (1996b), and Olsen et al. (2003).