Maps displaying the paleogeographical distribution of prominent land areas and major seaways existing during the early Cambrian to Silurian period are presented for the area east of the Canadian Shield (latitudes 56°–71° N, longitudes 110°–141° W). The paleographic reconstructions are based on isopach maps of successive Paleozoic rock units thought to be time equivalent. A relatively consistent pattern is seen.

The ancient continental margin includes a series of island arcs with attendant intercratonic, fore-arc and back-arc basins in a position approximately parallel to the present continental margin. These arcs show a northwest-southeast trend. Less well developed is a trend directed at approximately 70° to the systems of island arcs. It was first assumed that the pattern is a reflection of the Proterozoic paleotopography. However, through the early part of the Paleozoic period several of the paleogeographic features remain consistently positive, others consistently negative. This suggests some sort of tectonic control.

The early Paleozoic continental margin trends parallel to the present subcrop edge of the Early Paleozoic rock units. The distribution of the Cambrian rock units appears to be located further inland.

Many of the paleotopographic features described in this study continued to be active until the end of the Caledonian Orogeny.