;^S4 77/(3 A )nci'iriiii (re(>/</i/i.sL DccimhIxt, isn.') 
The C'onianche j^eries naturally resolves itself into terranes 
and horizons the character and degree of whose ditt'erentiation 
vary with the locality : but the grouping of these terranes into 
divisions is arbitrarj'^ and only ajiproximately expresses nat- 
ural relationships. The so-called divisions are usually con- 
nected by more or less important intermediate groups of 
sediments not projjerly referable to either. Where such a con- 
necting group is of considerable thickness and wide geographic 
extent, and is itself separable into minor subdivisions, such 
a group is probabh^ most naturally disposed of by considering 
it a division. The Kiowa shales, including the Kiamitia and 
the Tucumcari (or, in the Belvidere district of Kansas, the 
Black Hill, the Blue Cut and the Tucumcari) present these 
conditions and are therefore considered as constituting the 
Kioii'd (h'visioii. 
The Tucumcari terrane is not positively known to occur 
south of the Ouachita mountains, but Prof. Hill's record of the 
occurrence of (xnjpha'n I hck incdvli near Goodland, Indian 
Territory, suggests the probabilit^y that its horizon may be dis- 
tinguishable in the Choctaw Nation. 
The writer believes that the two groups of Shumard, the 
Washita limestone (including the Duck Creek, Fort Worth 
and Denton terranes) and the Arietina (for which the geo- 
graphic name Denison is ])referable, and which includes the 
North Denison, Pawpaw, Choctaw and Grayson) i-epresent 
divisions as natural as any, and that the sediments of the 
Texas-Arkansas (!omanche should be grouped in divisions as 
follows, the oldest unpreoccupied, reasonably brief*, strati- 
o'raphic names of geographic derivation being in all cases 
given the preference. 
('(tiiKi iivJie Series. . 
DIVISIONS. TEHKANES. 
Shoal Creek {of Hill). Not subdivided. 
Grayson (of Cragin). 
Deuison (of Hill). Choctaw (of Cragin). 
( Arietina, of Shiuuard.) Pawpaw (of Hill). 
North Denison (of Hill). 
*Stratigraphic terms, the geographic part of which consists of more 
than two words, are considered inadmissable. Hence the term. Trinity 
sandstone, takes precedence over the older one, Lower Cross Timber 
sandstone. 
