4 
MUSEUM BULLETIN NO. 29. 
York. The writer has likewise found it to be the most abundant species 
in the Portage horizon from central Pennsylvania 1 to southwest Virginia. 2 
This species is also one of the most abundant in the Simpson shale fauna. 
Because of the very wide geographic distribution of this fossil and its 
dominance in the fauna we may conveniently designate the fauna as the 
Buchiola retriostriata fauna. Ontario, clarkei, another pelecypod of this 
fauna, is also common to the New York and European Maniicoceras 
faunas. 
The relation of this fauna to other faunas of the region is indicated 
below. 
Upper 
Middle Devonian — Siringocephalus burtini fauna, Great Slave Lake section. 
Another fauna not yet sufficiently studied to permit detailed charac- 
terization appears to lie between the Buchiola retriostriata and Stringo- 
cephalus faunas. 
It is probable that the Portage fauna has a wide* distribution in the 
region to the westward of Mackenzie river. The writer 3 collected a 
specimen of Buchiola retriostriata on Yukon river below Eagle, some years 
ago. Collections made by Mr. Burling from the Canadian Alaskan 
boundary north of the Yukon also show a Portage fauna. 4 
We do not as yet know how the Portage sea of the Mackenzie-Yukon 
region was connected with the synchronous marine basin which occupied 
the upper Mississippi, Wabash, and New York area. The sections of the 
intermediate region along Athabaska river and in Manitoba show no trace 
of this fauna. 
Devon* an I Spirifer disjunctus fauna, Hay River section, 
j je vom an ^ Buchiola retriostriata fauna, Mackenzie River section. 
DESCRIPTION OF THE FAUNA. 
BRACHIOPODA. 
Cyrtina glabra n. sp. 
Plate I, figures 1, 2, and 3. 
Shell small with subpyramidal pedicle valve (apparently depressed 
because of crushing). Sides of ventral valve sloping regularly to the margin 
with a broad shallow sinus not reaching quite to the beak. Brachial valve 
convex in the umbonal and median portion and slightly convex near the 
anterior and lateral margins. Fold on pedicle valve showing only at 
front margin of shell. Cardinal area transversely striated and inclined 
forward. Deltidial plate not observed. Deltidial opening extending to 
the apex. 
The perfectly smooth surface of this shell distinguishes it from other 
species of Cyrtina. 
The species is represented by a single specimen only. 
Horizon and Locality. Simpson shale; bank of Mackenzie tiver 5 miles 
above Rabbitskin river. 
iU.S. Geol. Surv., Bull. No. 244, 1903, pp. 91-92. 
2 U,S, Geol. Surv., Bull. No. 508, 1912, p. 88. 
3 Brooks, R. A., and Kindle, E. M., “Palaeozoic and associated rocks of the upper Yukon, 
Alaska,” Bull. Geol. Soc. Amer., vol. 19, 1908, p. 288. 
4 Geol. Surv.j Can., Sum. Rept,, 1913, p. 317. 
