An overthrust involves older strata being pushed over younger strata at an angle less than. 로빈슨은 오버트러스트가 지구물리학적인 증거에 근거한 것이지 화석에 근거한 것이 아니라고 주장했습니다. This is true for some, but the Lewis overthrust in Montana and Alberta figures was identified based on fossils.