Plate Tectonics is a theory developed in the late 1960s, to explain how the outer layers of the Earth move and deform. The theory has caused a revolution in the way we think about the Earth. Since the development of the theory, geologists have had to reexamine almost every aspect of Geology. Plate tectonics has proven to be so useful that it can predict geologic events and explain almost all aspects of what we see on the Earth.
Steubenville is a city in and the county seat of Jefferson County, Ohio, United States. Located along the Ohio River, it had a population of 18,659 at the 2010 census.
The county is bounded on the north by Calhoun and Jackson Counties, on the east by Lenawee County, on the west by Branch County and Steuben County Indiana. The extreme southwest corner of Hillsdale County is where three states of Michigan, Ohio and Indiana meet, the only place where Michigan borders two other states.