24 Brachiopoda of the Cincinnati Group. 



Orthis emacerata — (Hax,l, 1860). 



Shell semi-elliptical, length and width about as 5 to 7 ; hinge line 

 nearly equaling the width of the shell. Dorsal valve flat, with a 

 slight depression down the center ; area extremely narrow. Ventral 

 valve depressed convex, slightly elevated at the beak, which is 

 inclined over the area, but scarcely incurved ; an undefined elevation 

 extending from the umbo toward the front, and sometimes quite to the 

 margin of the shell ; area narrow, almost linear. 



Surface finely striated ; stria? bifurcating, curving upward and 

 running out on the hinge line. Interior of the dorsal valve, with two 

 small teeth and a small cardinal process; valves thin. 



It is distinguished readily from the 0. testudinaria by the internal 

 markings of the valves, by the thinner shell and finer external 

 striae, there being at least 20 more on the margui of shells of equal 

 size. The depression in the center of the dorsal valve and elevation 

 in the center of the ventral valve are less cons]3icuous, and the hinge 

 line proportionally longdr, generally, than in 0. testudinaria. 



[This definition is from 13th Reg. Eep., N. Y., page 121.] 



It is found at Columbia avenue and Torrence road, 160 feet above 

 low water-mark. It was found in the excavation of Deercreek tunnel, 

 at the same elevation. It is not abundant, and seems to have a very 

 limited range. Having hunted the quarries at Hamilton, in Butler 

 county, and for other reasons that are elsewhere made apparent, I 

 do not believe that this form is found at that place, 'or in that horizon. 

 I have never known it to be found over 200 feet above low water- 

 mark, at Cincinnati. 



Prof Meek, in the Ohio Paleontology, described a shell as 0. emacerata, 

 and illustrated it with eleven figures, and gave the localities and 

 position for it at Cuicinnati, 250 feet and more above the Ohio, and at 

 Hamilton, in Butler county, Now, while I regard Prof. Meek as one of 

 the best and most careful paleontologists, and have freely copied his 

 labors in this monogi-aph, I am, nevertheless, quite confident that he 

 did not describe or illustrate the 0. emacerata, and that he did not have 

 the species before him. 



To account for this mistake, let us look at the following facts: Prof. 

 Me^k's figures, plate 8, figs. 2 a-g, are (I believe), Hamilton, Butler 

 county, specimens, and 1 a-d are from Cincinnati, or some other place. 

 He was, doubtless, informed, by some mistake, that these were identified 

 here, or known here as 0. emacerata, and after examining them, and 

 ascertaining that they were distinct from 0. tedudinaria, with exi^res- 

 sions of grave doubt he referred them to Hall's species 0. emacerata, 



