Strata and Relative Time

youngest to oldest
3-1-6-2-5-4
My Reasoning Notes:
3 is younger than 2
3 is younger than 6
3 is younger than 1
1 is younger than 6
2 is younger than 4
2 is younger than 5
My Explanation:
3 is younger than 2 because 3 is an intrusion and intrusions are always younger than the rock that they pass through. 3 is younger than 2, 6 and 1 because it passes through them all. 
1 is younger than 6 because the youngest layers on top and 1 is at the very top, and 1 is the layer above layer 6.

2 is younger than 4 because, 2 is an intrusion of 4, and intrusions are always younger than the rock that they pass through.
2 is younger than 5 because 2 is an intrusion on 5 so that makes it younger.