Danielson Crater is an impact crater in the Arabia quadrangle on Mars at 7.93° N and 7.11° W. and is 66.7 km in diameter. Many close up images of the crater reveal multiple thin layers, some of which are broken by faults. The layers on the floor may have been formed on the bottom of lakes. (wikipedia entry)
A crater is a circular depression likely created by an impact event. On Mars large craters are named after deceased scientists, writers and others who have contributed to the lore of Mars. Small creaters (less than 60km) are named after small towns and villages.