Where do you find the t-rex fossil in fossil fighters

Well,first you gotta beat the game then go to parchment dessert ok. next search the area for a dude (he's the only person there),then talk to him, then go to fossil guild shop,then pick today's special they are oasis seeds which cost 20 000 G (expensive) for 1. once you buy all of them go to parchment dessert then talk to the dude (he might be somewhere else) then you can find t-rexs!!!!!(how wonderful!)