Maryland Geological Survey 225 



right angles with the main stem ; leaves cut down to near the base into 

 two principal laciniae, and those higher cut into two or more minor 

 lacinise; ultimate lacinias very shallow and strap shaped, ending in acute 

 very short teeth, or rarely in narrowly elliptical and subacute ones; all 

 the lacinise turned outwards or upwards, the lower margins of the leaves 

 being entire or having sometimes an acute tooth; leaves in ascending 

 towards the tips of the leafy branches have their lower margins directed 

 more and more upwards, become smaller, assume more of an elliptical 

 or a wedge shape, have the lacinise only on the upper margin, and, finally, 

 coalesce to form a terminal leaflet, which at base shows three segments, 

 but whose terminal portions are not seen; nerves fine but distinct, 

 branching at base from a mother nerve, and then dividing repeatedly 

 in a dichotomous manner so as to fill the laminae, and have the branches 

 ending in the teeth. 



" The plant is most frequent at Fredericksburg, but is not abundant 

 there, and is usually in a very fragmentary state. If we look to the 

 shape of the leaves alone this curious plant is much like a fern of the 

 type of Adiantum, but the gradations through dilferent forms connect 

 the specimens so closely with the flabellate leaves of Baieropsis that they 

 cannot be separated by any good distinctions. The principal difference 

 from the more common and typical forms of Baieropsis is found in the 

 greater proportional width of the leaves and the smaller depth of the 

 subdivision." — Fontaine, 1890. 



This species is based upon very fragmentary specimens, and it is very 

 doubtful if the material identified from the Patapsco and Arundel forma- 

 tions is the same as that from the Patuxent, the presence of this species 

 from Chinkapin Hollow, Virginia, and Arlington and Fort Foote, Mary- 

 land, being each based on a single, very poor specimen. 



Occurrence. — Patuxent Formation. Fredericksburg, Lorton (Tele- 

 graph station), Potomac Run, Virginia. Arundel Formation. Ar- 

 lington, Maryland. Patapsco Formation. Fort Foote, Maryland ( ?) ; 

 Chinkapin Hollow, Virginia ( ?) . 



Collection.— JJ. S. National Museum. 



