Pteka. 



806 



397, figs. 426 a, a rhizome of this Devonian plant of the Gaspe 

 ^andstone formation in New Brunswick; 5, twig; c, end of a 

 branch; rf, venation; e^ fructification; long section of twig; 

 (all the above of natural size) ; g^ magnified areole of rhizome ; 

 A, omitted, given in another cut. — VIII-IX, — I. 0. White re- 

 ports it (doubtfully) in a Chemung hed^ 1,750 feet above the 

 top of the Oenesee, in his Danville section, Montour Co., Pa., 

 (G7, p, 307).— 7//7-iX 



Pteraspis. The internal structure of the shield of this Eng- 

 lish genus of Lower De- 

 vonian fishes {maqniUed 

 a hundred times linear) 

 is shown by a figure from 

 page 51 of the Quar. 

 Jour, of the London 

 Geological Society, to 

 illustrate Prof. Clay- 

 pole'sdescription of Fal- 

 se a s p i s americana, 

 and Palaeaspis bitrun 

 caDa* 



Fig. 2. Vertical longitudinal section showing (a) basal layer; 

 (h) cellular layer ; ((?) vascular layer, Q) lower por- 

 tion, (^) upper or tubular portion. 



Fig. 3. Vertical transverse section, showing (a) basal layer; 

 (h) cellular layer ; (c) vascular layer, (^) lower, (^) 

 upper portion. 



Fi^. 4. Horizontal section through vascular layer of shield. 



