64 ROYAL SOCIETY OF CANADA 
CoRDAITES NEWBERRYIT, (Dn.) Knowlton. 
Rae nl2: 
Bib. :—Dawson, Geol. Surv. Can., 1871, 14; Knowlton, U. S. Geol. Surv., 1889, 
37; Newberry, Jn’1 Cincin. Soc. Nat. Hist., 1889, 48-56; Knowlton, 
Proc. U. S. Nat. Mus., XII., 607. 
Dis.—Hamilton Group (Middle Devonian) of Ohio (Newberry); Carboniferous 
of Ohio (Claypole).: 
This species was originally described from material collected by 
Dr. Newberry, who has recorded its occurrence in the Huron Shales on 
Huron River in Erie County, and about Delaware and at various places 
in Southern Ohio.t In the same year Prof. Knowlton recorded its 
occurrence in the Carboniferous of Ohio as reported by Prof. Claypole.? 
The original description by Sir William Dawson is very inadequate," 
more especially as the characters are comparative with those of C. 
Hallii which is preserved only as an opaque object, and from which, 
therefore, a correct diagnosis cannot be obtained. The figures illustrat- 
ing this species are also inadequate, particularly with reference to the 
general distribution of the bordered pits and the tangential aspect of 
the medullary rays.* In 1889 Dr. Newberry undertook a revision of 
the microscopical characters, and called to his aid P. H. (now Dr.) 
Dudley, who made a very careful diagnosis of the structural characters. 
This agrees in essential points with my own diagnosis, and requires but 
little if any modification.” 
In a radial extent of 17 mm., this species shows no evidence of 
growth rings. Dr. Dudley says the layers of growth are wide but the 
limits not conspicuous,® but this seems to us clearly one of those cases 
in which the rings of growth are so poorly defined as to fall under the 
designation of obscure or obsolete. The tracheids are conspicuously 
squarish and somewhat unequal in their two diameters, but the walls 
are uniformly of about the same width." In a radial section the ray cells 
are seen to be of the one kind only, resinous and starch bearing. The 
lateral walls bear oval, bordered pits from 2-3 per tracheid, but chiefly 

1 Geol. Surv. Can., 1871, 14. 
2 Jn’1 Cincin. Soc. Nat. Hist., 1889, 48-56. 
5 Geol. Surv. Can., 1871, 14. 
ADI delle, UB. atkessh, ‘Ch, tely Ws 
5 Jn’1 Cincin. Soc. Nat. Hist., 1899, 54-55. 
5 Tbid, 54. 
7 The thickness of the tracheid walls in fossil plants is of no diognostic 
value, unless it is clearly unaffected by decay ; and even then its value is 
but slight. 

