PLATE XXIl—Conttnuecl. 



ICHTHYORACHr.S NeREIS. 



Page 66. 

 Fig. 19. A fragment of a frond, natural size. 



Lower Helderberg gi'oup. Schoharie, N. Y. 

 Pig. 20. An enlargement of the specimen fig. 19. 

 Fig. 21. An enlargement of the celluliferoua side of another si^ecimen. 



Sysocladia .' .sp. 

 Fig. 22. The noa-celliUiferous face of a fragment of undetermined relations. 



TiiEMAToroKA ? iiulct. - • 



Fig. ,, 23^ A , fragment, natural^^i;^., Introduced on this plate in error, and pi-eviouHly referred tu tbtf 

 following species. 



Thamniscus? Cisseis. 



Page ti. 

 A piece of rock with several fragments of the fossil on its sui-face. 

 2.'). This species as-sociated, on a piece of rock, with other species of Bryozoa and Aulopora. 

 A bi-anching frond, natural size. 

 A fragment enlarged ; the branch is twisted showing both the striate non-celluliferous side and a 



portion of the celluliferous surface. 

 An enlargement of the striated surface of a branch. 



An enlargement of the celluliferous face of a branchlet, showing, in some parts, granulose cell 

 margins, with some intennediate pustules or short spinules. 

 Fig. 30. The celluliferous face, partially worn, and with more circular apertures. 

 Lower Helderberg group. Near Clarksville, N. Y. 



Thamniscus ? Nysa. -^i'l 



"' ' Page 43. 



Figs. 31, 32. A branching fi-agment and an enlargement from the 8ame.io') 'tdJ lo lasmafu-. .'^i'-l 



Fig. 47. A fi-agment, natural size. 



Fig. 48. An enlargement of the preceding. li/i'J) 



Lower Helderberg group. Clarksville, N. T. 



Thamniscus fkucticella. 



,..,,, •.,,.■' Page *2. 



Fig. 33. The non-celluliferous fece of a branching form. 



^1 j^ ijj.^Thamniscu8 variolata. 



Page 41. 

 Fig. 34. A iX)rtion of a frond, natural size. 



Fig. 3.'5. A fragment showing a striated surface with cells on the margins of the branchlets. 



Fig.' 36. The celluliferous face of a larger fi*ond. 



Pig. 87. The non-celluliferous face of an unusually large frond, showing cells on the margins of the 



branchlets. 

 Pig. 38. The non-cellulifei-ons side of a fragment with closely-crowded branchlets. 

 Fig. 39. A fragment showing the smaller exti-emitiea of the branchlets. 

 Figs. 40, 41. Two fragments showing the characters of the frond near its base. ' "' 

 Fig. 42. A transverse section of a branch, showing numerous cellules. 



Pig. 43. An enlargement of the cell tubes, as seen looking vipon the lateral margin of a branch. 

 Fig. 44. An enlargement from the celluliferous lace of a branch and branchlets, showing the irregular 



_),,,•,.,„„ distribution of the cellules. ...di i.. n.iiiwil.'* fuli >iiiv/ -iiu ,hoi,i I, v. ,; / !k  ii-.;w a t' 



Fig. 45. An enlargement from the specimen fig. 36, showing the celluliferous face and a part of the striated 



surface. 

 Fig. 46. An enlargement of an irregularly-branching specimen, showing unequally distributed cell openings. 

 Lower Helderberg group. Near ClarksoUle, N. Y. 



