History of the North Sea great herring fishing industry resulting in Scotland becoming a European leader in that industry. During the First Schleswig War (1848–51), the Crimean War (1854–56) and the Second Schleswig War (1864), belligerents took steps to reduce or eliminate commerce in the North Sea by their enemies. In the first Schleswig War, Denmark was able to halt maritime commerce by Germany in the North Sea and in the second, imposed tolls on ships crossing through the Danish straits between the Baltic and North Seas. The Crimean War saw British and French expeditions sent into the Baltic to prevent Russian ships' egress into
Geology of the Baltic Sea Geology of the Baltic Sea The Geology of the Baltic Sea is characterized by having areas located both at the Baltic Shield of the East European Craton and the Danish-North German-Polish Caledonides. There is a distinction between what is the current Baltic Sea depression, formed in the Cenozoic Era, and the much older sedimentary basins whose sediments are preserved in the zone. Although glacial erosion has contributed to shape the present depression, the Baltic trough is largely a depression of tectonic origin that existed long before the Quaternary glaciation. The Baltic Sea sedimentary basin was formed on top of the