404 PALAEONTOLOGY OF ILLINOIS. 



PECOPTERIS DENTATA, Brgt. 



Veg. foss., p. 836, pi. 124. 



A fine species found in large specimens in the shales of the coal at Morris, 

 and also in the concretions of Mazon creek. 



PECOPTERIS FLAVICANS? Presl. 

 Sphenopteris flavicans ? Presl. 



Sternb., Vers., vol. n, p. 127. PL xxxviii, fig. 1, a, b, c. 



From Mazon creek also, and in concretions, we hare obtained a number of 

 specimens of a species which appears closely related to this species, if it is not 

 identical with it. They represent parts of fronds or pinnae, bipinnately divi- 

 ded ; primary divisions alternate, open, straight or slightly flexuous, linear, 

 bearing alternate, oblong, short, obtuse pinnules, connate at their base, slightly 

 decurrent, with a decurrent medial nerve ; alternately branching in simple 

 veins, two or three on each side, turning inwards in ascending or straight to 

 the border. The fruit dots are marked in a double row near the borders of 

 the leaflets, apparently placed upon the veins. The main rachis and its divi- 

 sions are deep and grooved. But for the position of the sori and of the thick 

 epidermis of its leaflets, this species could be referred to Oligocarpia Gutbieri, 

 Gopp., the disposition of the deeply marked veins and the form of the pinnules 

 being alike. As this Pecopteris flavicans is not mentioned by any recent au- 

 thor, not even by Unger, and as it is known only by the short description and 

 the incomplete figures given of it by Sternberg, our species is referred to it 

 with doubt. 



PECOPTERIS CIKEROPHYLLOIDES, Brgt. 



* 



It is remarked, vol. 2, p. 443 of ^his Keport, that this species was still un- 

 certain, having been found only in incomplete specimens. It has been ob- 

 tained since from the roof shales at Colchester in large and good specimens. 

 Except Pecopteris Cistii, Brgt., P. velutina, Lesqx., P. Newberryi, Lesqx., all 

 the species of Pecopteris enumerated in the 2d vol., have been since found in 

 Illinois. 



