BRADLEY: BRACHIOPODA OF THE MAQUOKETA OF lo\\\. 521 



width; is mm. in length; and 7 mm. in convexity. These dimensions 

 alone would suggest that this form belongs t<> the more common 

 Strophomena nutans and not (he larger variety, 8. concordensis, speci- 

 mens of w Inch frequently attain a width of L2 mm., a length of 30 nun., 

 and a convexity of 1 1 to L5 mm. 



Locality: This is a common Richmond fossil occurring in the 

 [Manchester division of the Waynesville bed in Butler, Warren, and 

 Clinton ( lounties, Ohio; also in the environs of Richmond, Indiana. 



Strophomena wisconsinensis Whitfield. 



Plate 1, fig. 7, S. 



Strophomena wisconsinensis WTiit field, Geol. Wise, 1882, 4, p. 263, pi. 12, fig. 

 11-13. Ball and Clarke, Pal. N. V., 1892, 8, pt. 1, p. 251, pi. 11 A, fig. 1, 2. 

 Foerste, Hull. sci. lab. Denison univ., 1912, 17, p. 108, pi. 7, fig. la-e; 

 pi. 9, fin. 5a-e. 



Evidently similar to specimens from the type-locality at Delafield, 

 Wisconsin are the two from Clermont, Iowa. They are characterized 

 by the great convexity of the brachial-valve which has a sudden 

 flattening toward the posterior part, and the regular generic depres- 

 sion near the beak. The cardinal area of the pedicle-valve is almost 

 parallel to the flattened surface. 



One specimen is distinctive not only for its peculiar specific idiosyn- 

 crasies, but also for a pathologic condition shown in the arrestment of 

 growth across the middle of the brachial-valve. 



Length, 17 mm., width, 24 mm., greatest convexity, 9.5 mm. 



The main difference between the specimens from Clermont and the 

 types is that the cardinal area is not nearly so high in the former as in 

 the latter. 



Locality: — Delafield, Wise, and Clermont, Iowa. M. C. Z. 8,541. 



Strophomena plaxodorsata W'inchell and Schuchert. 



Strophomena planodorsata Winchell and Schuchert, Amcr. geol. 1892, 9, p. 

 286. Geol. Minn., 1893, 3, pt. 1, p. 393, pi. 31, fig. 8-10. Foerste, Bull, 

 sci. lab. Denison univ., 1912, 17, p. 109, pi. 7, fig. 4a, b, 7a, b, 8; pi. 9, 

 fig. 6a, b, 7, 8a, b, 9, 11, 12, 14a, b. 



At Patterson's Spring near Brainerd, Iowa, the Niagara limestone 

 is well exposed. Below it lies a zone of shale six feet thick. Both 



