On the north-west of the continent the coast-line is much broken, the chief indentations being Admiralty Gulf, Collier Bay and King Sound, on the shores of Tasman Land.
The deep indentations of the gulfs of Bothnia and Finland are surrounded by what is ethnologically Finnish territory, and it is only at the very head of the latter gulf that the Russians have taken firm foothold by erecting their capital at the mouth of the Neva.
With the exception of Green and Traverse bays, Lake Michigan has few indentations of the coast line, and except at the north end it is free from islands.
The coast-line has few indentations sufficient to afford safe harbourage.
A peculiar feature of the hydrography of Tamaulipas is the series of coastal lagoons formed by the building of new beaches across the indentations of the coast.