land bridge

noun

1. Geology. an actual or hypothetical strip of land, subject to submergence, that connects adjacent continental landmasses and serves as a route of dispersal for plants and animals: a prehistoric land bridge between Asia and North America.
2. a transcontinental rail route between countries, as those in Europe and the Far East, considered faster and less costly than all-sea routes.

noun

1. (in zoogeography) a connecting tract of land between two continents, enabling animals to pass from one continent to the other