In order to correlate age-equivalent rock units of dissimilar ...

[Melani1276]

In order to correlate age-equivalent rock units of dissimilar composition or to correlate rock units over
  a large area, ___________________ _ and the principle of ___________________ _ must be used. Fill in the blank(s) with the appropriate word(s).

Question 2

The principle of ___________________ _ states that rock layers extended laterally in all directions
  unless or until they terminate in one of a number of natural means. Fill in the blank(s) with the appropriate word(s).

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Answer to Question 1

fossils, fossil succession

Answer to Question 2

lateral continuity

[Melani1276]

Wow, this really help

[dyrone]

Gracias!