PLEASE HELP ASAP!!!!!
which statement about the redwall limestone layer is true?
a. it is younger than Supai Group and Hermit Shale.
b. it is older than Muav Limestone but younger than Bright Angel Shale.
c. it is older than Muav Limestone and Bright Angel Shale.
d.It is older than Supai Group but younger than Muav Limestone.
