102 



Contributions to Palceontology. 



This Lingula characterizes the lowest fossiliferous beds of the 

 formation on the Upper Mississippi river near Trempaleau, and 

 opposite the mouth of Black river. 



LINGULA WINONA (n.s.). 

 PLATE I. FIG. 9. 



Shell small, subquadrilateral, the front nearly straight; 

 sides nearly straight and parallel : apex obtuse, the car- 

 dinal margins sloping at an angle of eighty degrees. 

 Surface marked by fine concentric striae. 

 This species occurs among some obscure and imperfect specimens 

 from Lansing in Iowa, and is readily distinguished by its short 

 broad form, being less than a fourth of an inch in length and 

 breadth. It is quite distinct from any of those in the lower or up- 

 per beds of the series; occuring more than two hundred feet below 

 the Lower Magnesian limestone, and near the middle of the Potsdam 

 sandstone. 



LINGULA MOSIA (n.s.). 

 PLATE I. FIGS. 1-3. 



Shell small, subelliptical or ovate-spatulate, little convex, 

 concentrically striated. The slopes below the beak are 

 sometimes nearly straight for a short distance, and often 

 curving from the beak to the base. The specimens are 

 for the most part impressions in sandstone, with little of 

 the shell remaining, but the form is very distinct from any 

 of the described species ; and being limited in vertical 

 range, and with a somewhat wide horizontal extension, 

 it becomes of interest in its associations. 

 I have given three varieties of form, which for the present I 



refer to a single species. 



Fig. 1. An elliptical form which presents some characters indicating a 

 distinct species, but which for the present I leave with the 

 others. 



Fig. 2. A specimen of the ordinary size, with nearly straight sides and 



front, and the cardinal slopes straight. 

 Fig. 3. An ovate form from the same horizon. 



Fig. 4. A more broadly ovate form from the Calciferous sandstone at Still- 

 water, Minnesota. 



