The Caraquet Dike has been mapped by ground magnetic traverses for a distance of 60 miles (97 km) between Caraquet and Wayerton, New Brunswick. A related lineament has also been recognized on aeromagnetic maps and confirmed at a few ground locations that would extend the dike and associated structural features for about another 250 miles (402 km) into the State of Maine. The age and trend of the dike support the idea that NW-SE tensile forces associated with the initial rifting of the Atlantic Ocean were operative in this nothern part of New Brunswick and Maine in late Triassic times. Post-intrusive offset faulting of the dike indicates changes in the initial stress system that could have been caused by variations in the rotational pole position during the subsequent opening of the Atlantic. Dike emplacement and faulting in former continental edges may therefore prove to be useful indicators of episodal changes in the development of ocean basins.