394 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 57 



DESCRIPTION OF PLATE 6i 



PAGE 



Dikelocephalus niinnesotensis Owen. (See pis. 60, 62, and 66) 369 



Fig. I. (One-half natural size.) Large cephalon flattened in shaly 

 sandstone. (85.) U. S. National Museum, Catalogue 

 No. 58602. 



2. (Natural size.) Cranidium for comparison with fig. 5. (85.) 



U. S. National Museum, Catalogue No. 58603. 

 The specimens represented by figs, i and 2 are from locality 85, 

 Upper Cambrian : St. Lawrence formation at Prairie du Sac, Sauk 

 County, Wisconsin. 



3. (Natural size.) Hypostoma associated with this species in 



locality 83^ Upper Cambrian : Uppermost horizon of the 

 St. Lawrence formation near Trempealeau, Trempealeau 

 County, Wisconsin. U. S. National Museum, Catalogue 

 No. 58604. 



5 and Sa. (Natural size.) Dorsal and side views of a cranidium 



preserving most of its natural convexity. (113.) U. S. 



National Museum, Catalogue No. 58606. 

 The specimens represented by figs. 4 (below) and 5 are from 

 locality 113, Upper Cambrian : St. Lawrence formation at La Grange 

 Mountain (or Barn Bluff), near Red Wing, Goodhue County, Min- 

 nesota. 



6 and 6a. (Natural size.) Top and side views of a pygidium pre- 



serving its natural convexity. From locality (3747 U. S. 

 N. M. records) Stillwater, Minnesota. U. S. National 

 Museum, Catalogue No. 3747. 

 7. (One-half natural size.) Doublure of under side of cephalon 

 with hypostoma in place. From locality 85X, Upper Cam- 

 brian : Upper beds of the St. Lawrence formation near 

 Mazomanie, Dane County, Wisconsin. U. S. National 

 Museum, Catalogue No. 58607. 



Dikelocephalus niinnesotensis var 371 



Fig. 4. (Natural size.) Small pygidium with strong spines. (113.) 

 U. S. National Museum, Catalogue No. 58605. 



Saukia crassimarginata (Whitfield). (See pis. 65 and 66 377 



Fig. 8. (Natural size.) Matrix of cranidium. This is illustrated by 

 Owen, 1852, pi. I, fig. 10, as D. {niinnesotensis ?), locality 

 La Grange Mountain, Minnesota (=113). Upper Cam- 

 brian: St. Lawrence formation at La Grange Mountain (or 

 Barn Blufif), near Red Wing, Goodhue County, Minnesota. 

 U. S. National Museum, Catalogue No. 58628. 



