Bearded Geology

On occasion, my home Internet router will reboot itself for reasons unknown to myself, and during one such instance recently, I was left realizing how much that I rely on the Internet these days and was unable to do much without it. However, since I use the Google Chrome browser, I was able to play the jumping T. rex game while waiting for my router to finish rebooting (press arrow keys on the "No Internet" screen to activate). While trying to beat my high score, I noticed that the dinosaur, some kind of tyrannosaurid (the T. rex family), was jumping over saguaro cacti. This got me wondering about the evolution of cactus plants and when they evolved. Cactus are flowering plants (aka angiosperms) and angiosperms evolved in the late Jurassic Period, and rapidly diversified during the Cretaceous Period. But, did the cactus (particularly saguaro) live at the same time as the dinosaurs? First, when did cacti evolve? Interestingly,“[t]here are no relevant fossil records