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MUSEUM BULLETIN NO. 2. 
to have been no recognition of the fact that in the original 
reference 1 a similar condition was acknowledged to exist in the 
Highland Range and Eureka District sections. Indeed the 
writer’s attention was only called to this fact after his curiosity 
had been aroused by noticing that the collections at the three 
localities (Big Cottonwood canyon, Pioche, and in the Highland 
range) were all made by the same field observers (C. D. Walcott 
and “J.E.W.”) during the same field season at a time (18S5) 
when the Olenellus fauna was believed by Mr. Walcott to be 
of Middle Cambrian age. 2 
A strong intimation of the fact that the Olenellus horizon was 
to be distinguished from that of the other fossils in both the 
Highland Range and Big Cottonwood Canyon sections was, 
however, given by Mr. Walcott five years earlier 3 when he 
said: “In both sections Olenellus comes first, and then Lingulella 
ella , Bathyuriscus producta , etc.” Here Mr. Walcott does 
not refer specifically to the collection from Pioche but on page 35 
of the same work he states that the “Pioche fauna was secured 
from beds 2, 3, and 4 of the section in the Highland Range,” 
where they have a combined thickness of 131 feet 4 and four of 
the species occurring at Pioche are stated 5 to occur also, though 
they are not so listed, in corresponding beds in the Highland 
Range section. The applicability to the Pioche collection 
of the remarks concerning the adjoining Highland range is, 
therefore, clearly shown. 
Two shale series have been identified in the vicinity of 
Pioche (see pages 96-98). The first collection from the lower 
shales, or the one to which the term Pioche formation has been 
applied, included two species of Olenellus only, and nowhere 
in their discussion of this fauna do either Gilbert 6 or White 7 
give the slightest indication that species representing other 
genera were included in the collections. This only corroborates 
1 Walcott: Bull. U. S. Geol. Survey, No. 81, 1891, p. 319. 
2 Idem, No. 30, 1886. 
? Idem, p. 39, section 76. 
4 At Pioche the thickness is given as 210 feet: Walcott, Smithsonian Misc. Coll., 
vol. 53, No. 1, 1908, p. 11; and 400 feet: Pack, School of Mines Quarterly, vol. XXVII, 
1906, p. 295. 
6 Waleott: Bull. U. S. Geol. Survey, No. 30, 18S6, p. 35. 
6 U. S. Geog. Surveys West 100th Meridian, vol. Ill, 1875, pp. 182-183. 
7 Idem, vol. IV, 1877, pp. 7 and 4A-18. 
