In prehistoric time, a great shower of nickel-iron meteorites collided with the earth near Odessa, forming the Odessa Meteor Craters about 20,000 years ago. Many thousands of meteorites of various sizes fell over an area of about 2 square mile. The smaller meteorites, which were by far the most numerous, either came to rest on the earths' surface or at the bottom of shallow impact pits within the soil. Several very large meteoric masses struck with enormous energy, penetrated deeply into bedrock, and shattered with explosive force, producing craters at the places of impact. When freshly formed, the craters were funnel-shaped depressions, the largest about 550 feet in diameter and 100 feet in depth, and more than 100,000 cubic yards of crushed rock was ejected from this crater. Smaller craters in the vicinity of the main crater ranged from 15 feet to 18 feet in depth. In the ages following their formation, the craters gradually accumulated sediments deposited by wind and water. The main crater was eventually filled to within 6 feet of the level of the surrounding plain and now appears as a shallow, nearly circular depression surrounded by a low, rock-buttressed rim. The smaller associated craters were so completely buried that their existence was not suspected until they were exposed in excavations made by the University of Texas in the early 1940's. Meteor craters are among the rarest and most interesting of land features, and observations by astrophysicists indicated that meteoric bodies striking the earth originate within our Solar System, probably from the asteroidal belt between Jupiter and Saturn.