i6 The American Geolocrist. January, 1904. 
years collecting. The shells from this locality are small, but well 
preserved and seem to be confined to a single zone associated 
with Acambona osagensis, Camarotoechia cooperensis, Pugiiax 
missouriensis, Reticularia cooperensis, Spirifer missouriensis, 
Spirifer latior, Spirifer pecnliaris and Spirifer osagensis. 
In May, 1900, professor Rowley* figured and described this 
shell under the name Retzia? raricosta, from the division 
No. 14 of the Louisiana, Pike county section. It is quite rare 
at this locality and never reaches dimensions greater than 7 
mm. long, 8 mm. broad and 4 mm. in thickness. With it 
are associated Amhocoelia levicula,Athyris lamellosus, Camaro- 
toechia cooperensis, Camarotoechia tuta, Cldothyris roissyi, 
Cleiothyris tenuiUeneata, Cyrtina hurlingtonensis, Dielasma bur- 
lingtoncnsis, Dielasma occidentale, Dielasma roivleyi, Nucleo- 
spira obesa, Productella arciiata, Prodnctella concsntrica, Pro- 
diictus laevicosta, Reticularia cooperensis, Rhipidomella biir- 
lingtonensis, Rhipidomella diminutiva, Rhipidomella thiemei, 
Rhynchopora pitstiilosa, Seminula bisinuata, Spirifer forbesi 
and numerous crinoids, corals and gasteropods. 
Near Cedar Gap, Wright county, Missouri, in the North 
View shale of Weller. P. sexplicata is of not uncommon oc- 
currence, being found in association with Cyrtina acntirostris. 
Athyris lamellosus, Rhipidomella missouriensis, Spirifer mari- 
onensis, Spiriferina clarksvillensis, Nucleospira barrisi, Reticu- 
laria cooperensis, Schizophoria szvalhzn, Camarotoechia cooper- 
ensis and Orthothetcs inflatus. The specimens from this local- 
ity are the largest so far observed, the average measurement of 
twelve of the best preserved shells being 11 mm. long, 12 
mm. broad, 5 mm. in thickness. 
P. sexplicata is also found in the very interesting shale depos- 
it at Fern Glen, St. Louis county. Mo. The writer's collection 
contains three specimens collected at this locality in association 
with Athyris incrassata, Athyris lamellosus, Athyris prouti. 
Leptaena rhomboidalis, Productella arcuata, Productus bur- 
lingtonensis, Spirifer grimesi, Spirifer forbesi, Spirifer pecnl- 
iaris, Rhipidomella missouriensis, Schisophoria szvallovi and 
Orthothetes cf. inilatus. 
Among some specimens recently received from Mr. Frank 
Springer, from the Lake Valley Mining District of Sierra 
• American Geologist, vol. xxv. May. 1900. Page 266, PI. V. fig's 34-37. 
