118 FLORA OF LOWER GOAL MEASURES OF MISSOURL 



The g-eneval phase of the Henry County, Missonri, specimens of 

 Alethopteris Serlii (Brongn.) Goepp., is ah-eady famihar to paleontologists 

 through figs. 2 and 4 given by Lesquereux on pi. xxix of the Coal 

 Fh:)ra. Of tlie nian\' fragments in tlie recent collections one, probably 

 belonging to a jjrimary pinna, shows a segment of a rachis 11 mm. wide, 

 slightly flexuous, with a moderately thick striated covering of coaly matter, 

 revealing, where the carbonaceous residue is removed, distinct impressions 

 of spines or spinous scales of considerable size passing from the back of the 

 racliis into tlie matrix. The midrib is irregularly striate in the larger pin- 

 nules. The lower pinna- are pinnatifid, even developing as tertiary pinnae, 

 all of the broad, blunt-pointed form referred to above and common in our 

 lower coals of both the anthracite and the bituminous series. 



Alethopteris Skrlii var. jiissouriensis n. var. 

 PI. XXXVII, Fig. 2; PI. XLII, Fig. 5. 



Although the normal form of the Alethopteris Serlii is frequent among 

 the fossils from this region of Missouri, the greater number of the speci- 

 mens, especially from one of the localities, which should be included under 

 that name quite uniformly present an aspect or phase more or less distinct 

 from any form I have yet met in the literature or in other collections. 



'I'lie normal form occurs more commonly in a fine-grained reddish- 

 gray shale from Owen's coal bank; and the specimens figured by Professor 

 Lesquereux have every appearance of coming from the same stratum if 

 not from the same place. The other form is found, with the exception of 

 the ferruginous concretions from Gilkerson's Ford, in a rather coarse, dark 

 dove or ash-colored shale having a slight tendency to check with a con- 

 choidal fracture in drying. 



Commonest among these specimens are large numbers of long second- 

 arv (?) pinnae strewn about on the shales, somewhat overlapping when 

 parallel, and clothed generally for their entire length with long simple, 

 rather distant })innules averaging 2 nun. apart, though frequently exceeding 

 4 mm., alwa}'s joined at an acute angle by the decun-ent lamina, and gen- 

 erally largest above the middle, and terminating in a more or less obtusely 

 acute point. The aspect presented is much like that indicated in Ettings- 

 hausen's fig. 4, Alethopteris Steriiber(/ii Goepp., on pi. xviii of the Flora of 



