Once a large part of the desert Southwest, was covered by an ancient sea. The way I understand it...volcanic activity started in places, causing lava to react with the water to form a rock, the surface texture similar to some meteorites you see in pictures. In some volcanic rocks, seashells are embedded along with traces of the ancient sea bottom.
Have you ever heard of black gold nuggets? These mostly are found in the Mohave desert and Salton Sea area of California. But they are volcanic without quartz, coated in a black iron mineral. This lava forced up through water created rocks with crystallised black iron mineral inside (lacking any quartz), a rusty looking brownish red coating on the surface. The black shows through where the coating is thin...giving a meteorite appearance to them.
Yours look rather weathered, but might be the same type of rock. Mine are very heavy, attract a magnet...but if they were meteorites, I'd be rich and wouldn't have to work anymore.