FLORA OF THE KOOTANIE FORMATION. 295 



the I'achis of the penultimate pinna, is constantly, in these specimens also, 

 abnormal in size and shape, being of the same character as in the Great 

 Falls forms. This is a constant and characteristic feature. The normal 

 or common pinnules also are essentially the same in character as those 

 from Great Falls, but are generally somewhat larger. The size of the 

 normal pinnules on some of the Ge^^ser plants indicates a fern consideral^ly 

 larger than the form most commonly occurring, and their shape is some- 

 what different. But these larger pinnules are connected in shape and size 

 by transition forms with the more common ones in such way as to forbid 

 a separation even as a variety. 



This fern, in the shape of its pinnules and in its nervation, strongly 

 reminds one of the Acrostichites forms seen in the flora of the Older 

 Mesozoic of Virginia. As, however, no fructification has been found on 

 an}^ of the specimens, it must be placed in the group of Cladophlebis, 

 which is based on nervation. It is true that this type of nervation departs 

 somewhat from the common types of Cladophlebis, but not enough to 

 prevent the placing of the plant in that comprehensive genus. In con- 

 sequence of the more complete and numerous specimens now found, the 

 character of the species must be corrected to read as follows : 



Fronds at least tripinnate; primary rachis slender; secondary^ pinnse 

 alternate, very remotely placed, slender and proportionally quite long and 

 narrow; pinnules, other than the inferior basal ones, of two kinds, those 

 that occur most commonly, which wejawff^all the normal ones, and those 

 less common, which, for distijje+i^n7may be called abnormal. The normal 

 pinnules are very smajif^ostly 2 mm. long and about as wide at their 

 bases. They are gesrerally remotely placed and are united at base, so as to 

 form a very narrqw wing on the rachis. In shape they are subrhombic to 

 suborbicular and very obtuse at their tips, or even rotundate there. The 

 longer ones are subfalcate, and all are united to the rachis by the whole of 

 a much widened base. The basal inferior pinnules of the ultimate pinnae 

 carrying these normal pinnules are much larger than the latter, and are 

 mostly flabellately 3-lobed, the lobes being shallow, more or less rounded 

 and obtuse. The nervation of the normal pinnules is strong but not very 

 sharply defined. It consists of a nerve bundle, which departs from the 

 rachis of the ultimate pinna much nearer the inferior then the superior 

 margin of the pinnule, so as to divide it into two very unequal parts. 



