Charles Lyells book 'Principles of Geology' explains all sedimentary rocks are deposited by extremely slow processes such as rain washing loose sand down a mountain slope to a river. Is this theory still current today? Or has it changed?
Landslides, floods, or other events could lead to faster depositing than rain washing loose sand down mountains. I would say the idea is incorrect.
the other thing i want to know is why geology and evolution are so closely linked? Shouldn't they be independent of each other?
They are independent. The are also linked in the same way that the topic of vehicles is related to the topic of highways.
I was afraid she'd conclude that you were saying that Lyell was wrong in general about how sedimentary layers form.
I should have seen the other angle that could be taken and I appreciate you pointing it out. I focused on the word "all" however and had flashbacks of creationists pointing a fossilized trees still standing and thinking the only way to deposit sediment quickly is via a world wide flood.