"It is confusing, from McKee's text and fig. 1 whether the tongue is assigned to the Muav formation or to the Bright Angel shale" (GNC note, n.d.). Meriwitica tongue [of Bright Angel shale of Tonto group] (USGS Bull. 1200); Meriwitica tongue [of Bright Angel shale of Tonto group] (USGS DDS-6).
Pg. 14 (fig. 1), 29, 80-82. Tongue is rusty-brown-dolomite unit in Bright Angel shale of western Grand Canyon. Composed of crystalline dolomite. Thickness at Meriwitica Canyon 16 feet. Separated from base of Muav formation by member of Bright Angel shale about 100 feet thick composed of shales and limestone. Lateral equivalent of certain limestone beds found in area west of Grand Canyon that probably constitute a member of the Muav, which is lower than any member within the Grand Canyon. Younger than Tincanebits tongue (new); older than Elves Chasm tongue (new). [On p. 29 age stated to be Early and Middle Cambrian and on p. 184 (part 2) Middle Cambrian. Age is considered Early and(or) Middle Cambrian.] Report includes measured sections, cross sections, faunal lists.
Type locality not designated. Present in western Grand Canyon. Traced along walls of canyon for many miles and extends eastward at least as far as Meriwitica Canyon. Origin of name not stated by author, but probably named from Meriwitica Canyon south of Colorado River, [Coconino and Mohave Cos., AZ].

Source: US geologic names lexicon (USGS Bull. 1200, p. 2470); supplemental information from GNU records (USGS DDS-6; Menlo GNULEX, Denver GNULEX), GNC index card files.

Meriwitica Tongue of McKee (1945) adopted as middle of three named units of Bright Angel Shale. Overlies Tincanebits Tongue and underlies Flour Sack Member, both of Bright Angel Shale; intertongues with Muav Limestone. Age is Middle Cambrian.

Source: GNU records (USGS DDS-6; Menlo GNULEX).