Late Newark Fault Versus pre-Newark Peneplain in Connecticut

Inferred structural features in S.-central Connecticut previously presented in favor of a pre-Newark peneplain have not been confirmed by recent detailed geologic mapping. Part of the western boundary of the E.-dipping Newark Group [Triassic] formerly interpreted as an unconformable contact now is known to be a fault of late Newark or post-Newark age. The irregularity of the boundary near Bethany Mountain is the result of differential erosion where relief on the pre-Newark surface is moderately high. There is no evidence for the oblique faults formerly inferred there to offset a pre-Newark peneplain. An irregular diabase sheet near the base of the Newark Group in that area is clearly dikelike at Bethany Gap and cannot be used as a marker bed for recognizing concealed faults.