220 MESOZOIC FLORAS OF UNITED STATES. 



Collection No. 5. — These come from the trail, about H miles northeast of Petty- 

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

 detached pinnules of a large fern of Cladophlebis type. Only one of these shows a 

 nearly complete pinnule, and much more and better material is needed to determine 

 the plant, for it is of a type that ranges from the Jurassic to the Upper Cretaceous. 

 The margins of this pinniile are finely denticulate and it may be Pteris Jngida Heer, 

 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 may be Gleichenia gracilis Heer, or 

 a small Dicksonia. Two specimens contain, one each, a fragment of an idtimate 

 pinna of a fern of Cladophlebis type smaller than the possible Pteris frigida Heer. 

 A number of species of this type also range from the Jurassic to the Upper 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 Pteris Alhertsii 

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



There are on three rock specimens small fragments of a leaf with anastomosing 

 nervation. The leaf is a small one and resembles a Sagenopteris. It Ta&j be a new 

 species. 



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

 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 Sapindopsis 

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

 There are also two fragments, on different rock fraginents, 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 be. 



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 number of dicotyledons than any of the others. 

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

 age of the strata containing them. Collection No. 2 is entirely too small to be of 

 value for determining age, even if all three specimens could 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 Aquia 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 the 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 metj belong. The 



