43 C.F.R. § 11.33
What types of assessment procedures are available?
There are two types of assessment procedures:
(a) Type A procedures are simplified procedures that require minimal field observation which can be used for all types of resources defined under this part (hereafter, all environments). Subpart D of this part describes the Type A procedures.
(b) Type B procedures require more extensive field observation than the Type A procedures. Subpart E of this part describes the Type B procedures.