With respect to their towns, later on, at an era of increased facilities of navigation and a greater supply of capital, we find the shores becoming the site of walled towns, and the Isthmuses being occupied for the purposes of commerce and defence against a neighbour.
"The History of the Peloponnesian War"
Thucydides
Cutting of Marine Isthmuses.
"The Earth as Modified by Human Action"
George P. Marsh
When we consider the number of narrow necks or Isthmuses which separate gulfs and bays of the sea from each other, or from the main ocean, and take into account the time and cost, and risks of navigation which would be saved by executing channels to connect such waters, and thus avoiding the necessity of doubling long capes and promontories, or even continents, it seems strange that more of the enterprise and money which have been so lavishly expended in forming artificial rivers for internal navigation should not have been bestowed upon the construction of maritime canals.
"The Earth as Modified by Human Action"
George P. Marsh