  The Frobenius depth denoted by $\Fdepth$ defined by Hartshorne-Speiser in
1977 and later by Lyubeznik in 2006, in a different way, for rings of positive
characteristic. The aim of the present paper is to compare the $\Fdepth$ with
formal grade, and $\depth$ to shed more light on the notion of Frobenius depth
from a different point of view.
