i i 1/, .1 i ;..n 



PLATE Xni-Continned. -i- 



.Hint • I'lOl / M.IJI I 



Stictopora papiixosa. 



Pijp. IS. A fig^are showing the mode of brtvochinf^ and arrang'einent of cell apertures. 



Lowor Helderberjj: group. Clarksmlle, N. Y. 

 Vig. 13. An eul&r^ment of a fragment showing' the foi-ni and arrang'eraent of the cell «peir(area. (X *i«) 

 Lower Heldei'bei-jf group. CtarkavUle, iV. Y. i« (i9»4qa 



I 



-mnalmueiwii iiKHiafmartfiatuihu'' PtiLODICTYA TE.VUI8. nalii J<r'>urHWi'i 



■■>wi<i lli»w^M«3(t«iii9n yinaayl'i-i •'. Pajre 39. 



■* See Plates 17, 23 a. 

 Fig. 14. An enlargement of the surface to show the mode of forp^tion o^ the intercellular longitudinal 

 partitions. 



Lower Helderberg group. Clarksville, N. Y. 



.hi) Kti 'lilt In i<mno1 ■\id\i'!iiu: •'i^'aVOSITES HeLDERBERGI^, ETC. ••■nil'iithMi'"' I«iittJ»n 



Fig. 15. A fragment of i'bwwifes HelderbergicB which has been overgrown by several other forms of corals 

 as i-epi-esented in the figure, each of which is indicated by a letter, as follows : a. Favonites 

 HelderbergicB ; 6. Fhvogites sphOBricux ; c. AlveoUtex explanafu.1 ; d. Pistulipora ponderosa ; 

 h. an inclosed cyathophylloid coral. The different expressions of Alveolites, c, are owing to the 

 direction in which the cells are cut in a plane section of the mass. 



Lower Helderberg group. Sclmliarie, ^. X* ^,fiiwfiilB lasnnja-rt ytnid-ynttui  



,„.„^,AW» fn^x^^^y^<^r.<\ ,Uh, ....i-,. ALVEOLITES EXPLANATU3. i„-„n^,1 



Page II. • , , , : . v.i in' 'y v. 



Fig. 16. An enlargement of the surface, showings the form acd 8t!'ia,tio» of the cell lipertures of the same 

 -»i.iq>( »Ji'speciea as shown in fl^. IBi aril ^ noiiiaoqaib <t6$ yiiwod^ ^ .^ on.-. 



hIU ^IflMla m tnm asluaiqa sdt anadv . LiCHBNALlA 8BRIALI8. 



Page 33. 

 See Plate 1.5. 

 Fig. 17. An enlargement of the surface to show the form and an-angement of the cell apertures 



Lower Helderberg group. ' Clarksmlle, N. T. 

 Fig. 18. An enlargement from the upper side of the 'epitheca, showing the procumbent position of the 

 cellules, and the strong lateral cell walls on the left-hand side of the figure, where the cellulea 

 have been broken away. in-iKr.  ^i'J 



Lower Helderberg group. ClarksviUe, N. Y. t-i9<i« llao 



I 



Fenestella Noe. 



- 1,1 II  , . r»»*%-u )j I ;n>-iw I 1/ I 



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



Lower Helderberg group. Ctarhmille, N. T. 

 Fig. 20. An enlargement of the non-celluliferous side. (X 6.) 

 Pig. "Jl. An enlargement of the celluliforous side of a specimen. 



Lower Helderberg group. Clarhtville, N. Y. 

 Kg. 22. An enlargement of the celluliferou.s side. (X 6.) .1 



.^,:■^■i,,■■■ Lower Helderberg group. ClarksviUe, N. Y. inaui-;^!'! 



r 



