78 The Saint Peter Sandstone. 



hingulepis morsii ( Winchell) S. A. Miller (1889), American Geology and 

 Paleontology, p. 352. 



A few specimens of this species have been found near Fountain, Fill- 

 more county, at the same exposure from which the type specimens are said 

 to have been collected. They differ somewhat from the original description 

 and figure but are no doubt the same. The shells are cuneate in outline, 

 moderately convex, with an apical angle of about 50 to60° (26°, Winchell). 

 The surface is smooth, with but slight concentric growth marks, and of the 

 usual green color, although in most specimens a deep iron coloration has 

 taken place. Radiating (not concentric) elevated rounded striae are present, 

 strongest near the anterior margin. 



The specimens figured are from one of the strata (c. fig. 9, pi. iv) of the 

 transition at the base of the Trenton (Galena) group, near Fountain Min- 

 nesota. 



Genus Orthis. 



Orthis perveta ? Conrad. 



Plate IV, figure 4. 



An imperfect specimen only was found, but so far as can be seen it is 

 like those that occur in the Buif limestone of the Galena series, that rests 

 above the shale [See pi. iv, fig. 9, c] in which this one was preserved. 



BRYOZOA. 



Genus Ptilodictya. 



Ptilodictya ? sp. ? 



Plate III, figure 15. 



The drawing illustrates an iron-stained imprint found at Highland 

 Park. No distinct characters remain on the fossil except the ramose out- 

 line, and evidence that it w^as flattened in one dimension like some of the 

 Bryozoa so abundant in the Trenton series. 



PORIFERA (Spongia). 



Genus Raufella. 



Raufella ? fucoida n. sp. • 



Plate IV, figures 5 and 6. 



The figures are of casts found at Fountain, Minnesota, associated with, 

 even containing, fragments of Lingula morsii N. H. W. They have some 

 imperfect surface marks w^hich, together with the general form, suggest 

 that they represent Porifera, the walls of which have served to mould sand 

 into internal casts and have since entirely disappeared. The casts are cyl- 

 indrical and branched at regular intervals like Raufella {ilosa Ulrich and 

 some other sponges of the Trenton series, and very much like an unde- 

 scribed species very abundant and associated with Licrophycus ottawaense 

 Billings in the Fucoid bed. 



