The Cambrian and Tremadocian sequences of the Acado-Baltic province have remarkable similarities on both sides of the North Atlantic, both faunally and lithologically. Stratigraphic breaks seem to be present at about the same levels--at the junctions of (1) the Lower and Middle Cambrian; (2) the Middle and Upper Cambrian; (3) the Olenus and Parabolina zones within the Upper Cambrian; and (4) the Upper Cambrian and Tremadocian. However, a section through the Upper Cambrian-Tremadocian contact on Navy Island, St. John, New Brunswick, shows at the most a small faunal gap.

The Cambrian and Tremadocian trilobite faunas in the Acado-Baltic province are referred to as the "Ellipsocephalid" (Lower Cambrian), "Paradoxidid" (Middle Cambrian), "Olenid" (Upper Cambrian), and "Ceratopygid" (Tremadocian) faunas. More work is needed on their paleoecology in order to evaluate fully their similarity on both sides of the North Atlantic.