The Boonton Formation is a distinct bedrock formation in New Jersey from the early Jurassic, about 197 to 190 million years ago, lying above the Hook Mountain Basalt and representing the uppermost continuation of the Passaic Formation as Pangea rifted apart. Once grouped within the old Brunswick Formation, it is now recognized separately. Its sandstone, siltstone, mudstone, and conglomerate record a shift from drier conditions to wetter intervals with lakes, shown by more gray, black, and purple layers among the red beds. It is especially important for a fossil fish bed, fish species, reptile and dinosaur footprints, plant remains, pollen, and for its unusually non-cyclic lower beds within the Newark Basin.