416 



PALEONTOLOGY OF OHIO. 



is a much smaller plant than the others, but, from a careful study of 

 many specimens, I am led to think it properly belongs to the genus 

 Megalopteris. Some fragments of another form of the same genus have 

 been found, but they are too imperfect for description. 



The Ohio species are of rare interest, not only for the beauty of the 

 plants, but because they are found, not in the Devonian, but in the Coal 

 Measures. Between them and any Ohio Devonian rocks are the Max- 

 ville limestone (equivalent of the Chester, Illinois, group) and the Lower 

 Carboniferous Waverly sandstone group. 



Megalopteris Harttii (sp. nov.). 



Plate 46, figs. 1 and lo. 



Frond very large, linear-lanceolate, somewhat enlarging towards the 

 top, simply pinnate. Rachis flat, striate, winged below the lower pinnae, 

 the alate portion extending lower in some specimens than in others, and 

 the external margins of the wings not always quite regular in outline. 

 Pinnae alternate, diverging at an acute angle, unequal-sided, the lower 

 side decurring and broad, and the upper narrowed toward the base or 

 medial nerve ; linear-lanceolate, obtuse, broadly decurrent, each extend- 

 ing down the rachis to the inferior pinna; margin distantly and irregu- 

 larly crenate, but often entire ; medial nerve flat, dissolving below the 

 apex. Veins very numerous and fine, diverging at a very acute angle, 

 forking twice or thrice, sometimes four times, and passing in a curve to 

 the border. This fine fern was about two feet in height. Fig. 1 shows 

 a terminal portion of the plant of natural size, but the medial nerves 

 are too prolonged; la shows the venation magnified. 



Found near base of Coal Measures, in Perry county, near Rushville. 



Megalopteris minima (sp. nov.). 



Plate 48, flgs. 1, la, 2, and 3. 



This species resembles M. Harttii, but is a very much smaller plant. 

 Rachis striated. Frond simply pinnate. Pinnae lanceolate and some- 

 times acuminate, comparatively short and narrow, strongly decurrent, 

 connected above the base ; margin entire ; midrib flat, as in M. Harttii, but 

 extending nearer to the apex. The nerves fork two or three times, as in 

 M. Harttii, but are more open and diverging, coarser, and less numerous. 

 In M. Harttii the nervules diverge from the medial nerve at a very acute 



