120 
MUSEUM BULLETIN NO. 2. 
a gradational series of beds in which the transition is from the 
more clastic to the less should be included with the younger, 
and ( b ) that the introduction of new faunas, even of new types 
in faunas preserving more or less of their original character, 
is a phenomenon attending the inception rather than the decline 
of stages in the earth’s history, the Albertella fauna seems to 
have achieved the right to be classed with the Middle Cambrian. 
THE PIOCHE FORMATION. 
The Pioche formation was first described in 1908 1 when 
Pioche, Nevada, was cited as the type locality and it was stated 
to carry the Lower Cambrian Olenellus fauna. Later in the 
same year 2 it was described for the House Range section of 
western Utah and accompanied by a list of the fossils at Pioche, 
an assemblage which is compared in the following table with a 
list first published in 1886. 3 
Fauna of strata (“2, 3, and 
4“?) resting on the quartzite 
at Pioche, Nevada, 1886 . 4 * 
Fauna of the Pioche forma- 
tion at Pioche, Nevada, 
1908. 6 
Fauna of the Pioche for- 
mation at Pioche Ne- 
vada, 1912.® 
Eocystites?? longidactylus. . . 
Lingulella ella 
Kutorgina pannula 
Acrothele subsidua 
Acrotreta gemma 
Orthis highlandensis. . 
Hyolithes billingsi — 
Olenellus gilberti 
Olenoides levis 
Crepicephalus augusta 
Crepicephalus liliana. . 
Eocystites? longidactylus 
Obolus (Westonia) ella 
Micromitra (Ipliidella) 
pannula 
Acrothele subsidua 
Acrothele subsidua hera. . 
Acrothele spurri 
Acrotreta primoeva 
Billingsella highlandensis.. 
Hyolithes billingsi 
Olenellus gilberti 
Zacanthoides levis 
Crepicephalus augusta 
Crepicephalus liliana 
Micromitra (Iphidella) 
pannula. 
Acrothele subsidua. 
Acrothele subsidua hera. 
Acrothele spurri. 
Acrotreta primoeva. 
Billingsella highlandensis.. 
Hyolithes billingsi. 
Olenellus gilberti. 
Zacanthoides levis. 
Crepicephalus augusta. 
Crepicephalus liliana. 
Olenoides sp. 
Ptychoparia sp. 
Oryctocephalus primus. 
iWalcott* Smithsonian Misc. Coll., vol. 53, No. 1, 1908, pp. 11-12. 
2 Idem, No. 5, 1908, p. 184. 
*Walcott: Bull. U. S. Geol. Survey, No. 30, 1886, p. 35. 
Hdem. 
^Smithsonian Misc. Coll., vol. 53, No. 5, 1908, p. 184. 
6 Mon. U. S. Geol. Survey, vol. LI, 1912, p. 192. 
