2 74 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, Panelling 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^, 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 cherty layers. At Thedford (Widder) Ontario, this 

 northwestern Delaware fauna occurs in a series of beds^ which 

 resemble somewhat those that outcrop along Ten Mile Creek. 



The following list of species gives some idea of the Devonian 

 fatma in the above section: 



TEN MILE CREEK FAUNA. 



Species Columbus Delaware 



Stroriatopora granulata Nich x 



Stromatopora pondcrosa Nich x 



Cladopora canadensis Rom x 



CyatliDphyllum rugosiim H x 



Cystiphyllnm amencanitm E. and H x 



Diphyphyllum. panicum Win x 



Favositcs arbitscida H x 



Favositcs hayniltoniac H .x 



Favositcs liciuisphcrica Tr x x 



Favositcs nitclla Win x 



Favositcs placenta Rom .x 



Favositcs radiciformis (?) Rom x 



Hcliophyllnni Iialli E. and H x 



Streptelasma uiii^iihi H x 



('•i) Geological Survey of .Mic-hi,L,'an. vol. \'I1, ji]). 'Al '.V.i. 



(4) Geology of Canada {IHiY.i) p. ;i8.5. 



Also Grabau ; Bullelin of the Geological SocicLv of America, vol. 

 XIII. (1902) ])p. ir)()-1.52. 



