428 THE PALEONTOLOGY OF MINNESOTA. 
[O. germana. 
The specific name is after A. D. Meeds of the University of Minnesota. 
Associated with the above species, at its climax of development in number of 
individuals, a very characteristic and striking variety makes its appearance, which 
is named germana. 
Formation and locality.—Rare near the base of the Galena shales at St. Paul, Minnesota, and 
McGregor, Iowa, a few feet above the horizon of O. pectinella and variety sweeneyt. It becomes a common 
and very characteristic fossil in the beds immediately above, and is there associated with Clitambonites 
diversa Shaler; it is known to extend for thirty feet above this horizon. ‘ 
The following are the most prominent localities at which this species has been collected: Cannon 
Falls, Kenyon, Warsaw. Fountain and Preston, Minnesota; Decorah and McGregor, Iowa; Neenah and 
Oshkosh, Wisconsin. 
Collectors.—W. H. Scofield, E. O. Ulrich and the writers. 
Mus. Reg. Nos. 4055, 5860, 5861, 6746, 7771-7785. 
Variety Germana W. and S. 
PLATE XXXII, FIGS. 48—45. 
1892, Aprill. Orthis meedsi var. germana W. and S. _American Geologist, vol. ix, p. 290. 
This variety is distinguished from O. (D.) meedsi by the following characters: 
Smaller in size and squarer in outline; valves more strongly and more evenly 
convex; hinge areas nearly equal in width and narrower, with the beak of the 
ventral valve slightly elevated above that of the dorsal; ventral valve with a slight, 
somewhat angulated fold, while the dorsal has a shallow, but distinct sinus origin- 
ating immediately below the apex of the valve. The fold and sinus produce a slight 
sinuosity in the anterior margin, the direction of which is just the reverse of that in 
O. (D.) meedsi. 
The largest specimens of this variety observed have the general external expres- 
sion of small individuals of Orthis subquadrata, and no external nor internal parts 
are known that preclude the form from being viewed as the ancestor of that species 
which attains its specific development in the upper portion of the Cincinnati group 
The beds from which var. germana is obtained are fully one hundred feet below those 
holding O. subquadrata. During this interval no specimens of Dinorthis have as yet 
been detected. 
Formation and locality.—Not rare in the upper part of the Galena shales at several localities south 
of Cannon Falls, near Kenyon and Fountain, Minnesota. This horizon is also characterized by Anastro- 
phia hemiplicata and a number of small Bryozoa. 
Collectors.—W. H. Scofield and the writers. 
Mus. Reg. No. 7770. 
Orruis (DInoRTHIS) SUBQUADRATA Hall. 
PLAT XXXII, FIGS. 46—50. 
1847. Orthis subquadrata HALL. Paleontology of New York, vol. i, p. 126, pl. XxxIIA, fig. 1. 
1862. Orthis subquadrata HALL. Geology of Wisconsin, vol. i, p. 54, figs. 1, 2. 
71863. Orthis subquadrata BILLINGS. Geology of Canada, p. 165, fig. 146. 
