888.1 PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 7 



ire partially filled with a dark mass representing the resin. (PI. n, 

 ig. 4.) 



Tangential section. — In this section the medullary rays are observed 

 o be composed of a single series of cells which ranges from 3 to 30 in 

 mmber. It is rare, however, to find them with as few as 3 or as many 

 ls 30 cells, the average number being from 8 to 15. 



Bordered pits have not been observed in this section. 



This beautiful species is one of the most clearly marked of any that 

 las been described. It is apparently related with several that have 

 >een described from Russia, but it differs in important particulars from 

 ill. Thus it resembles the Cupressinoxylon sequoianum Mercklin,* which 

 las the wings only one-half to 2 mm broad; sometimes three or four 

 eries of bordered pits, and 1-40 or more superimposed cells in the 

 aedullary rays. From Gupressinoxylon sylvestre Merckl.t it differs, as 

 he latter has one, rarely two, rows of pits on the radial walls of the 

 racheids and the medullary rays, 2-15 cells high. Gupressinoxylon 

 anguineum Merckl.f has the pits in one, or rarely in two, irregular series, 

 ldcI the rays are composed of only 2-18 superimposed cells. 



The specimens are completely chalcedonized and stained a yellowish 

 )rown color. As to their age Mr. W. J. McGee informs me § that " there 

 s every probability that the Emmet County, Iowa, wood is from the 

 Jretaceous, though it has been found in the drift, the Cretaceous strata 

 ? rom which it was originally derived having formerly extended over 

 ;ontiguous parts of Minnesota- and been largely removed by glacial 

 erosion during the Quaternary." Specimens from Martin County, Minn., 

 ire indistinguishable from the Emmet County specimens. 



Gupressinoxylon elongatum, n. sp. Plate in, figs. 1-4. 



Diagnosis. — Annual rings apparent to the naked eye but faint, one- 

 lalf to 6 mm broad ; tracheitis thick-walled, provided with two, rarely one, 

 •ows of bordered pits on radial walls; medullary rays numerous, com- 

 posed of short thin-walled cells, arranged in a single series of from 1 

 o 44 superimposed cells j resin-ducts moderately abundant, composed 

 )f a chain of short cells. 



Locality.— Tiger Buttes, Dawson County, Mont. Age, probably Lar- 

 imie group. 



MICROSCOPIC ANALYSIS. 



Transverse section. — The layer of fall-wood separating the contiguous 

 Ings is narrow, consisting of only six to ten rows of flattened and thick- 

 called cells. The cells of the spring and summer wood are much larger 

 tud nearly rectangular in outline. Their radial diameter is as great as 

 105 mm in some cases, while the tangential diameter is only .035 to .04 umi . 



* Palaeodendrologikon Rossicuru, p. 05, PI. xvn. 



t Op. cit., p. 58, PI. xm, figs. 1-6. 

 J Op. cit., p. 57, PI. xn. 

 § In litt., January 4, 1888. 



