Streetcars in North America Streetcars in North America Electric streetcars or trolley(car)s (North American English for the European word "tram") were once the chief mode of public transit in hundreds of North American cities and towns. Most of the original urban streetcar systems were either dismantled in the mid-20th century or converted to other modes of operation, such as light rail. Today, only Toronto still operates a streetcar network essentially unchanged in layout and mode of operation. Older surviving lines and systems in Boston, Cleveland, Mexico City, Newark, Philadelphia, Pittsburgh, and San Francisco were often infrastructure-heavy systems with tunnels, dedicated right-of-way, and long travel
Geology of North America Geology of North America The geology of North America is a subject of regional geology and covers the North American continent, third-largest in the world. Geologic units and processes are investigated on a large scale to reach a synthesized picture of the geological development of the continent. The divisions of regional geology are drawn in different ways, but are usually outlined by a common geologic history, geographic vicinity or political boundaries. The regional geology of North America usually encompasses the geographic regions of Alaska, Canada, Greenland, the continental United States, Mexico, Central America, and the Caribbean. The parts of the