274 
The Ohio Naturalist. 
[Vol. VIII, No. 5, 
measuring the angle of dip at various points, the total width of 
outcrop, and from this data computing the thickness of the beds. 
The Delaware, however, was measured more accurately. The 
Columbus limestone in this section is not essentially different 
from the same formation as found in other parts of the state. 
The upper or very fossiliferous portion is perhaps slightly reduced 
in thickenss and its fauna is somewhat different. This is not so 
much because of the appearance of new species, but because of 
the absence of certain characteristic Columbus species, which 
are so common in central Ohio. The shales and shaly limestones 
of the Delaware (Traverse), however, present a rather marked 
contrast to the rock of this formation as it occurs in central or 
even north central Ohio. In the section under discussion, the 
fauna is more decidedly Hamilton, there is more shale, and the 
limestone is even less pure than at localities east of the Cincinnati 
anticline. A small outcrop of this same shaly limestone occurs 
along Auglaize River near Junction, Paudling county, where it 
carries an identical fauna. 
There can be no doubt that the Delaware (Traverse) of north¬ 
western Ohio is an integral part of the Hamilton of Michigan and 
Ontario. It is continuous northward into Monroe county (Mich¬ 
igan) where is has been reported in various well sections 3 , and the 
formation as it occurs farther north, along St. Clair River, is 
certainly the same. Here it has become much thicker and has 
lost its chertv layers. At Thedford (Widder) Ontario, this 
northwestern Delaware fauna occurs in a series of beds 4 which 
resemble somewhat those that outcrop along Ten Mile Creek. 
The following list of species gives some idea of the Devonian 
fauna in the above section: 
TEN MILE CREEK FAUNA. 
Species Columbus 
Stror.iatopora granulata Nieh. 
Stromatopora ponderosa Nich. x 
Cladopora canadensis Rom. 
Cyathophyllum rugosum H. x 
Cystiphyllum americanum E. and H. 
Diphyphyllum panicum Win. 
Favosites arbuscula H. 
Favosites hamiltoniae H. 
Favosites hemispherica Tr. x ... 
Favosites nitella Win. 
Favosites placenta Rom. 
Favosites radicijormis (?) Rom. 
Heliophyllum halli E. and H. 
Streptelasma ungula H. 
(3) Geological Survey of Michigan, vol. VII, pp. 31-33. 
(4) Geology of Canada (1863) p. 385. 
Also Grabau; Bulletin of the Geological Society of America, vol. 
XIII, (1902) pp. 150-152. 
Delaware 
. . x 
. . x 
. . X 
. . x 
. . x 
. . x 
. . x 
. . x 
. . X 
. . X 
. . X 
. . X 
