162 :mesozoic floras of united states. 



of the original one. The specimens in the collections from Alaska show 

 that pinnsp in the position on the frond shown in Dunker's specimen are 

 longer then these, although they are remarkably short for foliage of such 

 size. This fern has an uncommon aspect, and it resembles so closely the 

 specimens from Alaska that there can be no doubt that they l;)elong to 

 the same species. The general aspect is somewhat like that of Thinnfeldia. 



The specimens collected Ijy Mr. Dumars show that the plant must 

 have been of large size and that it was probably arborescent. One of 

 Dumars's imprints, with much of the lower and upper parts wanting, 

 shows a compound pinna 32 cm. long, with a rachis of the maximum 

 width of 5 mm. This is probably a fragment of a pinna and not of the 

 frond. The specimens are not very well preserved, as the rock is unfavor- 

 alile. ijeing a sandstone with little tendency to cleave. The pinnules are 

 generally a good deal distorted and fragmentary, so that their normal 

 character can be made out only by a careful examination of all the parts 

 and by taking many pinnules. The large fragment represented in PI. 

 XLI, Fig. 1, is probably a compound pinna from well down on the frond. 

 The plant is somewhat different in aspect, according to the position on 

 the frond of the parts. The following may be given as its character: 



The plant was probably arborescent and of large size. At least a 

 tripinnate character is indicated. The pinnse of superior order must have 

 had a very considerable length, as indicated in the fragment 32 cm. long, 

 which was probably originally twice as long. This is probably only a 

 penultimate pinna. The ultimate pinnae in middle portions of the frond, 

 as shown in PI. XLI, Fig. 1, are short in proportion to the size of the 

 pinnules. Xone are shown entire, but a few are almost so. The largest 

 of these is 85 mm. long. They go off ol)liquely from the main rachis and 

 curve slightly away from it. The pinnules were thick in texture and 

 apparently leathery. The largest pinnules, in l^asal portions of the 

 lower pinnae, are about 2 cm. long and 9 mm. wide in the widest part. 

 They diminish in width and length toward the ends of the ultimate 

 pinnae and in terminal portions of the compound pinnae. Some of the 

 pinnules of larger size are 25 mm. long and only cS mm. wide, but this 

 variation is probably due to distortion from pressiu'e. The distortion 

 and mutilation of the pinnules seem universal, and it is impossible to find 

 a single one not affected. Hence the specimens, when drawn as they now 



