I think you're not entirely wrong, but the dinosaur remains are fossilized, and that requires special conditions.
I know a load of human remains and accouterments were found in bogs.
Regards to the glaciers, I suppose there are ranges of effects. The Canadian Shield had all topsoil shorn away, in most places even now it's just a few feet of soil then granite.
BirAdam was referring specifically to ADVANCED CIVILIZATIONS. People who build cities (latin civitas). Many of them, in many places, including places where stuff stays put for millions of years. Mines, quarries, tunnels and canal excavations don't get wiped away. Debris on the ocean floor doesn't get wiped away.
We're not talking about people living in mud huts who only eat fruit, haven't discovered fire, and leave no archeological traces; likewise we're not talking about hyperintelligent dolphins who went extinct, or aliens that landed briefly 4 billion years ago on a continent that got subducted. If you want to talk about the non-discoverability of something that isn't an advanced civilization, go ahead, split that hair.
Given enough time, a shell midden becomes limestone.
Children of a future civilization might not find out anything about our culture or language, but they are definitely going to know that we loved oysters. Meanwhile, their scientists will argue about what kind of iron-rich oysters are responsible for the remains of reinforced concrete along our prehistoric shores and rivers.
I know a load of human remains and accouterments were found in bogs.
Regards to the glaciers, I suppose there are ranges of effects. The Canadian Shield had all topsoil shorn away, in most places even now it's just a few feet of soil then granite.
https://en.wikipedia.org/wiki/Canadian_Shield#Ecologyq
In such areas, nothing survived. Shell middens would be wiped away.
I may have over stated, but my point was it won't be as easy as some think.