Knowledge of the Quaternary geology and sequence of events has developed spasmodically, more or less dependent on the pace of systematic mapping. A century ago in the early days of the glacial theory, and in the initial reconnaissance phase of geological exploration, attention was focused mainly on determining the direction and sequence of glacier movements. Although this approach was prompted by economic considerations, specifically the search for gold by means of displaced erratics, it did serve to successfully elucidate the general pattern which showed the activity of local glacial centres. Study of uplifted shorelines supported the concept of two independent ice domains on Newfoundland and the Maritimes, separated by a largely ice-free Gulf of St. Lawrence which Laurentide glaciers infrequently invaded.
Then, for several decades in this century, while regional fieldwork declined in popularity, the notion became entrenched that the last event was an invasion by a single northern ice sheet, as in the mid-continent region, and that all radial patterns were late, local, short-lived diversions consequent on marine calving of the super ice sheet. In the last 15 years resumption of systematic surveys and special stratigraphic studies have revalidated the original concept that while the Wisconsinan glacial stage may have included an intermediate regional ice sheet phase, it began and ended as a complex of coalescent local ice caps, some of which were at times situated on the emergent shelf.