J SIikIji of the liclrldcrc licds. — C rut/in. '^^l 
shells, ^yhich are, however, associated with other species, among 
which two of the most constantly abundant are Canliion kan- 
sa.seiise and I'in-n'telUi .seyi<itih}'(ir<t mtlafa var. kiiiisaseii.sis. 
The occurrence of the Duck Creek shell, fnoccra mus co- 
mancheainis^ in these shales is noteworth3^ 
All of the vertebrate and nearly all of the invertebrate fos- 
sils listed from the Kiowa shales have been found in the Ful- 
lington beds, including the upper portion of the Black Hill, 
and all, l)ut especially the lower part, of the Blue Cut shales. 
The lower part of these shales presents locally a ''tish-bed" 
horizon in which occurs Linguhi, associated with numerous 
small shark's teeth and fragments of teetli and spines, recalling 
the so-called "fish-bed" of the Benton in its composition. 
Fossils generally are neither so abundant nor so well pre- 
served in the upper, usually lighter-colored jjortion of the 
Blue Cut shales as in the lower portion. But to this rule we 
see exceptions in Otifrea fra nkUiii, Gnjitluva rncmcri and 
Exixjijra texdna, the first of which occurs in solid ledges with 
either of the two latter, or other shells as intruders, and the 
second of wdiich occurs also finely petrified in the soft shale and 
sometimes in such numbers as to constitute loose beds, though 
rarel}'^ rock-ledges like those of <). J'ra iiklini. Sclilocuhdrhln 
peruviana, (' upriiiicria k/oirdju/, and indeed almost any of 
the fossils that are abundant in lower horizons of tiic Blue 
Cut shales, occur occasionally, and in more westerly localities 
even commonly, though rarely well preserved, in the upper 
horizons also. 
THE TUCUMVARI H HALES. 
The shells of the genus (iriipluva increase in size as found in 
successivel}' higher horizons of the Belvidere beds from the 
appearance of the genus in the Champion shell-bed to its dis- 
a[)pearance just below the base of the leaf-bearing fiei'dcr 
(Dakota?) sandstone which surmounts tiie Kiowa shales in 
the upper valley of the Medicine Lodge river near tiu^ post- 
otfice at Reeder. The largest examples are found in the upper 
Kiowa shales of the Otter Creek district. Some of these seem 
most nearly related to Gnjpluvd rocuieri : l)ut others clearly 
belong to G. fncumcarii, particularly to that phase of the 
latter that Mr. Jules Marcou has called ^'. (Uliiinhi : whih- 
others still represent various intermediate forms lietwi'en the 
