88 
dextral one, with the knobs and growth lines oblique downward to the 
right, and if the figures given are of natural size (length of three whorls 
28 mm., breadth of largest whorl 18 mm.) our specimen is much smaller; 
there is also in ours a slightly greater difference between the upper and 
lower slopes of the whorls. 
CORRELATION AND CONCLUSIONS AS TO AGE 
Succession of Strata 
Jurassic (lowest) 
Lias 
Shasta co., California 
Rhaetic 
Norio 
Pseudomonotis shales 
Coral reef zone 
Upper Triassic 
Karnic 
Tropites limestones 
Halobia shales 
Ladinic (Upper) 
Distribution of Species 
Species 
Locality 
A 
B 
C 
D 
E 
Isastrea whiteavesi C. and S 
r 
r 
1 
1 
1 
I. Vancouver ensis C. and S 
r 
C 
2 
Calamophyllia suttonensis C. and S 
C 
c 
3 
3 
3 
C. dawsoni C. and S. 
? 
c 
4 
Montlivaltia cf. gosaviensis Freeh. 
R 
X 
Terebratula suttonensis C. and S 
R 
R 
Plewomya pearsonensis n. sp. 
R 
Megalodon canadensis n. sp 
c 
Myophoria sp. 
c 
Turcicula mccanni n. sp 
r 
Localities: A "Pearson creek; B "Vancouver island; C = Shasta co. f California; D=Iliamna 
lake, Alaska; E=Ziambach fauna. C=very common; c= common; r=rare; It = very rare. 
The numbers refer to the following closely related species in the Zlambach fauna of the Salz- 
kammergut district: 1, Isastrea profunda Reuss; 2, Coccophyllum acanthophorum Freeh; 3, Thecos- 
milia fenestrata Reuss; 4, T. oppeli Reuss. 
Since the publication of the original discussion 1 of the age of the 
isolated Sutton formation there has appeared a brief discussion 2 of appar- 
ently the same fauna from coral reef beds in Shasta county, northern 
California, from the Blue mountains, Baker county, northeastern Oregon, 
and from Pilot mountain, Esmeralda county, Nevada, where, fortunately, 
the fauna occurs in a known succession, with well-defined, fossil-bearing 
beds above and below. These sections definitely place the age of this 
i Clapp, C. H., and Shimer, H, W., “The Sutton Jurassic of the Vancouver Group, Vancouver Island," Froc. 
Boston Soc. Nat. Hist. , 34, pp. 421-438, 1911. 
* Smith, J. P., "The Occurrence of Coral Reefs in the Triassic of North America,” Am. Jour. Sci. (4) 33, pp 
92-96, 1912. 
