174 E. H. Barbour — Carboniferous Plant Tissue. 



dry it curls like thin shavings, but upon immersion in water 

 straightens out nicely. It is readily handled in the laboratory, 

 for it can be dehydrated, stained, cleared of coal particles, and 

 imbedded and sliced for examination. 



We have about one hundred permanent mounts in our 

 collection. The tissue varies from fragments to pieces 10 

 millimeters wide by 75 long. Most of it, under transmitted 

 light, is a bright transparent yellow, ranging to orange, red, 

 brown, and blackish, according to the amount of iron and 

 ulmate. All mounts show cell structure well, and photomicro- 

 graphs are readily obtainable. 



Apparently these pieces of tissue are the resistant cuticular 

 layers of certain leaves. Two or three distinct kinds have 

 already been noted. The cells are sub-parallel to parallel in 

 arrangement, and are interspersed by numerous stomatous 

 openings. The still greater number of small circular openings 

 probably represent truncated epidermal hairs. 



As far as examined, the bulk of the material, especially the 

 larger pieces, seem referable to Cordaites. Such tissue has had 

 occasional mention in Europe and America, but the Nebraska 

 material seems unique in amount and excellence of preservation. 

 As many as fifteen to twenty pieces to the square foot have 

 been noted. 



This problem has been assigned to a Fellow in the Depart- 

 ment of Geology, the University of Nebraska, for careful 

 study and publication. The material is a part of the geological 

 collections of Hon. Charles H. Morrill. 



University of Nebraska, Lincoln, Nebraska. 



