PLATE G. 



PAGK. 



1 tO 3. CVUNDROCtELIA MINNESOTBNSIS UlriCh* 78 



1 . A small specimen, covered in part by a bryozoan; natural size. Also end view of 

 same, showing numerous unequal canals. 



2 and 3. A large fragment having canals of unusual size; and an end view of the same; 



natural size. Upper part of the middle third of the Trenton shales, St. Paul, 

 Minn. Collection of E. O. Ulrich. 



Figs. 4 to 6. HETEROSPONGIA SUBRAMOSA? Ulrich 79 



4. A fragment of the natural size, doubtfully referred to this species. Hudson River 



group, Spring Valley, Minn. Collection of E. O. Ulrich. 

 5 and 6. Vertical and tangential sections, x 10, of a typical specimen from Cincinnati, O. 



Figs. 7 to 9. HINDIA PABVA Ulrich 79 



7. Three specimens of this species, showing extremes in size so far observed. 

 8 and 9. Vertical and tangential sections x 10. Upper third of the Trenton shales and 

 Galena shales, Goodhue and Fillmore counties, Minn. Collection of E. O. 

 Ulrich. 



Figs. 10 to 13. LICHENARIA TYPA, gen. et. sp. nov 83 



10. A large colony of this species growing upon a fragment of Callopora incontroversa 



Ulrich, x 2. 



11. A small colony in which one of the buds has grown in a manner suggesting 



Aulopora, x 5. 



12. A longitudinal section through a large colony. Trenton shales, Minneapolis, 



Minn. University of Minnesota collection. 



13. A small free mass of this species, of the natural size, and a portion of the same x 3. 



The latter shows at a, and in the space to .the right, a pore passing from the 

 parent tube into the base of the buds. This fact is important in this that it 

 indicates a relationship of Liclienaria with the Auloporidcc, rather than with 

 Columnaria, where we have placed the genus provisionally. Middle third of 

 the Trenton shales, St. Paul, Minn. Collection of E. O. Ulrich. 



Figs. 14 to 16. COLUMNARIA (?) HALLI Nicholson 85 



14. A portion of the surface, to show the septal ridges. Trenton shales, St. Charles, 



Minn. Minnesota Geological Survey collection. 



15. Part of a vertical section, enlarged five times, showing the tabulae. (After 



Nicholson.) 



16. Part of a transverse section, showing the amalgamation of the walls of the coral- 



lites and the marginal septa. (After Nicholson.) 



Figs. 17 to 19. STUEPTELASMA PKOFUNDUM Owen 88 



17. View of a natural cast of the visceral cavity, the usual mode of occurrence in the 



Trenton limestone, Minneapolis, Minn. 



18. An entire specimen in which a portion has been broken away to show the great 



depth of the body cavity. 



19. View of the visceral cavity, showing the three fossulae and the counter septum. 



Base of the Upper Buff limestone, Mineral Point, Wisconsin. Minnesota Geo- 

 logical Survey collection. 



Figs. 20 and 21 . STKEPTELASMA COKNICULUM Hall 90 



20. An exterior view of a specimen broken so as to show the depth of the visceral 



cavity. 



21. View of the visceral cavity to show the twisted nature of the septa. Galena 



shales, St. Paul, Minn. Minnesota Geological Survey collection. 



Figs. 22 and 23. STREPTELASMA UUSTICUM Billings 93 



22. The exterior of an imperfect specimen. 



23. View of the visceral cavity, showing a distinct pseudocolumella. Hudson River 



group, Granger, Minn. Minnesota Geological Survey collection. 



Figs. 24 and 20. PHOTAR^CA VETUSTA Hall, sp 94 



24. A colony of this species growing on a fragment of a strophomenoid shell. 



25. A portion of same, enlarged five times, showing the septal ridges. Hudson River 



group, Spring Valley, Minn. Minnesota Geological Survey collection. 



Figs. 26 to 28. AULOPORA (?) TRENTONENSIS, n. sp 95 



27. A view of a colony of this species; natural size. 



26. A portion of same enlarged three times. 



28. An unusually well preserved specimen growing upon Batostoma winchelli Ulrich, 



of the natural size and a portion x 3.5. Middle third of the Trenton shales, 

 Minneapolis, Minn. Collection of E. O. Ulrich. 



* The drawings for figures 1 to 9 are by Mr. Ulrich. 



