Yellow Cat area is North of Moab. It is just South of I-70. The exit from Utah is marked as such. If you are traveling West the exit is just marked "Ranch Exit". It is a large area but well picked over. Nonetheless, there is still a lot of spectacular material to be found by the adventurous. Climbing offers the best chance of finding good material just because most people don't do it. If you go, stay away from the mine. It is a uranium mine and my gieger counter went wild anywhere within several hundred feet. There is a grape agate area just above the mine but it is also hot and just a quick walk through it convinced me that not only is it not worth it but there is very little left anyway. The petrified wood is among the best in the world and there is always the chance of finding dino bone fragments. For the life of me I can't remember the mineral but there are lots of red bubbly nodules that are pure white inside. Most are less than one inch but if you are there for long it is likely you will find larger ones.