84 FLORA OF LOWER COAL MEASURES OF MISSOURL 



Although the stratigraphic position of the beds near Clinton would 

 seem to be rather low for this form, it has ah-eady been reported in speci- 

 mens/ which seem to me questionable, from beds no }-ounger at Mazon 

 Creek, Illinois, as well as from Mount Hope, Rhode Island.' 



Locality. — Pitcher's coal mine, U. S. Nat. Mus., 5663. 



Pecopteeis squamosa Lx. 



1870. Pecopteris squamosa Lesqiiereux, Rept. Geol. Surv. IlliDois, vol. iv, p. 400, pi. 



xii, figs. 1-4, pi. xiii, figs. 10, 11. 

 1879. Fecopteris squamosa Lesquereax, Coal Flora, Atlas, p. 7, pi. xxxix, figs. 12, I'i, 



13a; text, vol. i (ISSO), p. 235. 

 1899. Pecopteris squamosa Lx,, D. White, 19tb Auu. Rept. U, S. Geol. Surv., pt. 3, p. 494. 



The species from Mazon Creek, Illinois, described by Lesquereux 

 under the above name is one of the smallest of the genus Pecopteris. It is, 

 as seen in numerous specimens from Cannelton, Pennsylvania, somewhat 

 conspicuously characterized by the rigid, close, narrowly linear, very open 

 pinnae, tapering from the base to the slender, acute apex, and the small, 

 narrow, open, crowded, villous pinnules. The iippermost pinnee and pin- 

 nules are extremely small and delicate. The nervils are very open, simple 

 in the smaller pinnules, forking once in the lower pai-t of the larger ones. 



The specific details of this plant are given with tmusual fullness by its 

 author in the Coal Flora,^ and should be carefully consulted by anyone 

 making a comparison of the species with other forms. Unfortunately, 

 illustrations of the ordinary and typical fragments are still lacking. 



The specimens sent by Dr. Britts from Missouri are in perfect agree- 

 ment with those from Mazon Creek and Cannelton. One fragment of a tri- 

 pinnate frond from the last-named locality contains a segment of a rachis 

 16 mm. in width, provided with close, linear-lanceolate acuminate pinnae 48 

 cm. in length. The obliquity of these lateral pinnae with reference to the 

 rachis would seem to indicate a position for them in the upper part of the 

 frond, which, in that case, must have been of great size. A number of 

 examples from the same place show the pimise well preserved in nervation. 

 It should be remarked that while the features of the pinnae and pinnules 

 remain the same in both the old and the young specimens, the squamosa 

 character is often less obvious in some of the large segments. 



' Lesquereux, Geol. Surv. Illinois, vol. iv, 1870, p. 401. 

 - Am. Nat., vol. xviii, 1884, p. 922. 

 »Vol. i, p. 235. 



