220 MESUZOIC FLORAS Ui- LMTKD STATES. 



CoUeciion No. J.— Tlicst' come from the trail, about 1 h luilos northoast of Petty- 

 john's rancli. The collection contains 22 specimens. Six of them show scraps of 

 detacheii ])innules of a lar<:e fern of Cla(loj)hlebis type. Only one of these shows a 

 nearly conijjlete ])inniile, and niiicli nioic and better material is needei! lo determine 

 the i)lant, for it is of a type that ranges from the Jurassic to the Up|)er Cretaceous. 

 The margins of this pinnule are hnely denticulate and it may be PtcnsJ'rUjlda Ileer, 

 from the Atane beds of Greenland. 



There are two specimens that contain each a small fragment of an ultimate 

 pinna with a few poorly preserved pinnules that nniy be Gleiclicniu t/ivcilis I leer, or 

 a sniah Dicksonia. Two specimens contain, one each, a fragment of an ultimate 

 pmna of a fern of Cladoplilebis type smaller than the possible Pferis frigida Heer. 

 A number of species of this type also range from the Jurassic to the I'pper Cretaceous, 

 and the material is not sufficient to determine the true place of this plant. It may 

 very well be a small form of Dryopteris Oerstedi (Heer) Kn., or Piiiis Alhertsii 

 (Dunk.) Heer, both found by Heer in the Atane beds of Greenland. 



There are on thi-ee rock specimens small fragments of a leaf with anastomo.sing 

 nervation. The leaf is a small one and resembles a Sagenopteris. It may be a new 

 species. 



Several specimens show scraps that are apparently leaves of some dicotyledon, 

 but they are not sufficient to indicate even generic position. There is one fragment, 

 and one nearly complete leaf, of a dicotyledon that strongly resembles Sapindopds 

 parvifolia Font., a plant confined to the Aquia Crepk horizon of the Lower Potomac. 

 There are also two fragments, on different rock frag.nents, of a dicotyledon that was 

 of larger size than the one last described. This looks like a Sapindopsis, but the 

 specimens are too incomplete to give a hint as to what species it may b(\ 



One fragment has the shape and size of Nageiopsis longifolia. It is a detached 

 leaf showing neither base nor tip, and no nerves; hence it is not possible to deter- 

 mine it. 



This collection has a larger numl)er of dicotyledons than any of the others. 

 Collection No. 1 has nothing determinable, and hence the plants give no hint of the 

 a^e of the strata containing them. Collection No. 2 is entirely too small to be of 

 value for determining age, even if all three specimens coidd be determined. The 

 only determinable plant is a dicotyledon of rather modern aspect. So far as it goes, 

 it indicates an age not greater than the Acjuia Creek stage of the Lower Potomac. 

 It, however, may be of the age of the Atane or Upper Cretaceous of Greenland. 

 Collection No. 3 has no dicotyledons, and if we look to these alone, this would indi- 

 cate that the formation yielding it is somewhat older than that of collections Nos. 2 

 and 5. From only 12 specimens, however, it would be unsafe to draw negative con- 

 clusions. The age of this may be either Lower Potomac or Atane. Collection No. 4 

 is remarkably free from dicotyledons, and as this is th(^ largest their absence has 

 more significance. It taken alone would indicate an age somewhat greater than that 

 of collections Nos. 2 and 5. The plants indicate a Cretaceous age, but do not decide 

 between the Lower Potomac and Atane, to either of which they may l)elong. The 



