Dinosaurs existed, but they were mass buried in a catastrophic Flood -- the one in Genesis.
The bone sorting, smallest-to-largest deposition pattern, everything -- only the Flood as chronicled in Genesis explains the evidence.
Layers were put down VERY quickly, one on top of the other, and the biggest head-scratcher: there was no time for burrowing insects to disturb one layer, or rain to erode it in all the various low points, before the next layer was deposited. Only a catastrophe could do that.
There are some great pro-Creation videos on Youtube that go into all these details.
https://www.youtube.com/playlist?list=PLEVsU6O-XMpG0mzwS98OhPfYekQRnA93K