Table 3. Different Types of Underclay at Joggins: according to Logan and Dawson; 
               Dawson's contributions are  italicized and in Red.

 Coal
 Group
 Bituminous
 Limestone
 (Ancient
 soil bed) ??
 Sandstones and
 Argillaceous
  Sandstones
 (Understones)
  Arenaceous
     Shales
 (Underclays)
    Argillo-
  arenaceous
      Shales
 (Underclays)
 Argillaceous
 (Gray) Shales
 (Underclays)
 Carbonaceous
  Shales (below
 Coals or above
   Underclays)
    1       1 (Understone)
  w/ Stigmaria ficoides
 Rootlets
         1
 w/ Stigm. ficoides
 Sandstone, Gray,
 Rootlets of Stigmaria
         1
 w/ Stigm. ficoides
 Rootlets
        
    2        1
 Rootlets of
 Stigmaria;
 erect tree also
 rooted in this
 limestone.
         1
 w/ Stigmaria ficoides
         1
 w/ Stigm. ficoides
 Underclay w/
 
Rootlets of
 Stigmaria
   1-3 (?) Inferred
 from Dawson, 1868
 No Stigmaria
 Clay, Clay, Shale
 (each  between
 layers of coal)
    3          1
 w/ Stigm. ficoides
 Underclay w/
 
Rootlets
    4          1
 w/ Stigm. ficoides
          1
 No Stigmaria
 Underclay, hard
 and arenaceous,
 Stigmaria rootlets.
           3
 No Stigmaria
 Shale, bituminous
 and pyritous, Coaly
 layers, Poacites,
 Ulodendron.
    5          1
 w/ Stigmaria leaves
         4
 3 w/ Stigm. ficoides
 1 w/ Stigm. leaves
    6       1 (Underclay) w/
 branches and leaves  of  Stigmaria  ficoides
         1
 w/ Stigmaria
    7           1
 w/ Stigmaria
          3
 No Stigmaria
    8        1 (Understone)
 w/ Stigmaria and
 upright Calamites
         1
 w/ Stigmaria
         1
 w/ Stigmaria
          3
 1 w/  No Stigmaria
 1 w/ Stigmaria
 1 w/ Stigm. ficoides
          1
 No Stigmaria
    9        1 (Underclay)
 (Rough  gray
 sandstone) w/ Stigm.
         1
 w/ Stigmaria
         1
 w/ Stigm. ficoides
   10          1
 w/ Stigm. ficoides
     1 (Shale-like
  Underclay)
  No Stigmaria
          1
 No Stigmaria
   11          1
 w/ Stigm. ficoides
          1
 No Stigmaria
   12        1 (Understone)
 w/ Stigmaria
         1
 w/ Stigm. ficoides
          1
 No Stigmaria
 Totals        1
 Rootlets of
 Stigmaria
            5
 3 w/ Stigmaria
 1 w/ Stigmaria ficoides 
 1 w/ branches and
 leaves of  Stigmaria
 ficoides
         4
 1 w/ Stigmaria
 2 w/ Stigm. ficoides
 1 w/ Stigm. leaves
         12
 2 w/ Stigmaria
 9 w/ Stigm. ficoides
 1 w/ Stigm. leaves
         9
 2 w/ Stigmaria
 5 w/ Stigm. ficoides
 3 w/ No  Stigmaria
 13-15
 No Stigmaria in any
  of these beds

After Logan, 1843 (pub. 1845); Division 4 Coals, Coal Groups 1-12;  And Dawson, 1853,
Q. J. Geol. Soc. Lon., V. 10, pp. 3-6;  Dawson, 1855,  Acadian Geology, pp. 129-135
(Rom. Num. XXVII--XIX),  these contributions are in red italics.  See also: Dawson, 1868,
Acadian Geology,  pp. 162-167.

Definitions:
Stigmaria
  is the generic name given to the roots of the Sigillaria tree. 

Stigmaria ficoides are the roots of the Sigillaria tree; however, they are recognized by (and known for)
the round pit marks (or dots) that are all over them.  These dot/spots are evidence of the areolae to which
rootlets were once attached.

Stigmaria leaves  are the rootlets which were once attached to larger Stigmaria (ficoides) roots.

Underclay is a generic term that is used to denote (what is thought to be) a fossil soil.  Sometimes they
are referred to as "seat-earths".

Notes and Comments:

Dawson lists a (2 inch) Bituminous Limestone (underclay) with  "Rootlets of Stigmaria" 
at the top of Coal Group 2 (in the middle of XXVII).