PLATE XXIII. 
BUGS ALbO}8: ACALGOPOR AsD UMATIS oN ISD mets cccterctalecist eistsieisclole ie ners sfols Samal] «mia velaehte mot ele cipisters eis taste 282 
l1to4. Representative fragments of the natural size. 
5. Surface of the slender piece 9. 
6. Surface of another that preserves the zocecial closures, <18. 
Tand 8. Vertical and tangential sections <18. 
Upper third of the Trenton shales, St. Paul. 
Wigs) .95 10) 2landi29) “CATLTORORA  GOODHIUENSISj 1118p ic «/-\-tejsicisieisistaeeois lols ol atelnyele eee eretotcyelsieipiaiet-ieietelalers 282 
9and 10. Two fragments of the natural size. 
21. Axial region of a transverse section 18. 
29. Surface of a specimen 9. 
Galena shales near Cannon Falls, Minn. 
Wigs. 1) 12) 16; 17,,24-26; 30) 31. CALLOPORA MULTITABU LATA IIc. c cwle cise eicfeiei cise #0 ele nic oP eiecieiere 280 
1land 12. Montiferous examples, the latter but slightly, from the Galena shales at Cannon 
Falls. 
16. ‘Typical specimen from the upper third of the Trenton shales at St. Paul. 
17. Tangential section *18, of the Galena shales form. 
24. Vertical section of a specimen like fig 16, <9. 
25. Surface of the original of fig. 16, <9. 
26. Surface of a very finely preserved specimen x18, showing the ornamental zocecial 
closures. Upper third of the Trenton shales, St. Paul. 
30. Surface of a specimen like the one from which the illustrated tangential section (fig 17) 
was prepared, x9. The figure includes one of the clusters of large zocecia. 
31. Surface of a typical specimen x9. 
Wigs 13-15; 18-20) 2202321, ose OAL LOPOR A RAMP ANT ISD heaeee seers chienienaeielatclars icine sige rrcastetaeiees 281 
13. A large irregular specimen from the Galena shales at Cannon Falls. 
14and 15. Two typical examples from the base of the upper third of the Trenton shales 
near Fountain, Minn. 
18. Tangential section X18, of another specimen from the same horizon and locality as 
the preceding. 
19. Vertical section of the same *9. x 
20. The axial region of a transverse section of the same X18. 
22. and 23. Portion of one zocecial tube of a vertical section and a tangential section, <18, of 
a specimen like figs. 13 and 28. Galena shales, Cannon Falls. 
27. Surface of the original of fig. 14, x9. 
28. Surface of the original of fig. 13, x9. 
Figs. 32 to47. DEKAYELLA PRM NUNTIA, n. sp., and varieties. : 
Megs 320088.) Val. CHUNATAGuTUn valerate sisetteise icon Sa OU GA OM eANO ONO ANG to oasaEeeboens 271 
32.- Typical example of this variety. : 3 
33 and 34. A less compressed fragment of the natural size and a portion of its surface x9. 
35 and 36. Two portions of a tangential section 18. 
37. Vertical section-of the same specimen x9. ; 
Lower part of the upper third of the Trenton shales near Fountain, Minn. 
38. Portion of a tangential section of a specimen from the upper part of the middle third 
of the Trenton shales at Minneapolis; x18. Other parts of this section are precisely 
as in fig. 36, but in the portion figured the mesopores are larger and more abundant 
than usual for this variety. The vertical section of this specimen is indistinguishable 
from fig. 37. 
Migs, S0ito42.\ Vari SUMP LAR. Mr cveID ccm si rtetccicte ates seat staetake ere ce RTeIs er To eet 271 
39. Tangential section 18, of a specimen with thick walls. 
40. Verysmall portion of the superficial region of a vertical section magnified 50 diameters to 
show the minute structure of the walls and the method of depositing the diaphragms. 
41 and 42. Small portions of two tangential sections 50, the first with walls as in figs. 39 
and 40, the second with thinner walls, parts of which are marked transversely. 
Lower third of the Trenton shales, Minneapolis. 
Fig. 43. The TyPIcaAL FORM of the SOC Bacumacodcco, cob nono aenanedno onswacndanounde soobeh adeaoaos 270 
An average tangential section x18. Middle third of the Trenton shales at Minneapolis. 
Wigs. 44:to 47.” Wars MULTIPORAs NV Ale pewter s ceinecitee ati s oto ea eee ee ee ee 272 
44, A tangential section x18, with very thin walls and small acanthopores. 
45 and 46. Another tangential section with stronger walls and large acanthopores, x18, and 
several cells X50. 
47. Vertical section x18. 
Middle third of the Trenton shales,Minneapolis. 
