I think this is original remains because its body look vary nicely intact.

This is an replaced remains fossil because its bones and tissue are replaced with different kinds of minerals.

#3 is the youngest because its a intrusion and cut up through everything else.

#1 is the next youngest because it is on top all the other layers of rock.

#6 is the next youngest because its the next layer below layer #1.

#2 is 3rd to oldest because it is an intrusion above layers #5 and #4 but below layers #1, 3 & 6.

#5 is the 2nd to oldest because its layers are above #4's layers.

#4 is the oldest because it is below layers #5.