FLORA OF THE TRINITY FORMATION. 333 



a large amount of other Lower Cretaceous, chiefly Potomac, miscellaneous 

 material, and he reported upon it at the time that he sent on his report 

 on the Potomac flora of Virginia and Maryland, in November, 1902. 

 In this report he says: 



About 50 rock specimens occurred in the collection from Plaster Bluff. The 

 material is a fine-grained, lumpj^ shale, light ash-gray to nearly white in color, which 

 has no cleavage. The shale, or rather the indurated clay, is full of small bits of 

 vegetable matter, most of which are much comminuted and not identifiable. The 

 only fossil that can be certainly identified is Frenelopsis varians Font., a plant charac- 

 teristic of the Glen Rose beds of the Trinity group in Texas. This plant here shows 

 only the internodes of the twigs, rarely more than the length of one internode being 

 found m any one bit. The twigs seem to have been broken at the joints. Hundreds 

 of these fragments are embedded in the clay. The firm, durable epidermis seems 

 to have preserved very well the fragments, some of which are verj^ distinct, showing 

 the rows of minute tubercles on the surface, and the peculiar teeth-hke leaves at 

 the nodes. There is no doubt whatever that the twigs are jointed. A few bits in 

 the clay suggest the presence of PagiophyUwm dubium Font., another character- 

 istic plant of tke Glen Rose beds. The fragments are, however, too obscure to be 

 positively determined. 



We next proceeded to the typical localities in western Texas, arriving 

 at Glenrose, in Somervell County, on October 9. We had secured an 

 outfit the previous day at Granbury, Hood County, and were thus enabled 

 to study the formations passed over in traveling south to Glenrose. 

 After passing Comanche Peak we entered the Paluxy sands, in which 

 quantities of silicified wood occur. A citizen of Glenrose, Mr. J. W. 

 Harvey, formerly of Cincinnati, where he had made collections from the 

 Cincinnati group, had been active in collecting the shells of the country 

 and had made a museum of his house. Besides the rich local fauna, he 

 had a few vegetable impressions that interested me much. The locahty 

 at which they were obtained was on the Paluxy River 2 miles above 

 Glemose, and on the following day Mr. Harvey guided the party to the 

 place and the day was spent in collecting the plants and associated 

 animal remains. The bed lies in the Glen Rose limestone, and character- 

 istic marine fossils of that group occur immediately above and below 

 the plant layer. It is a white argillaceous limestone, cleaving in smooth 

 layers which are rather thick. The plants occur throughout these layers. 

 The matrix is fine grained and well adapted to preserve them, but tends 

 to break across with a somewhat conchoidal fracture. It was obvious 



