TEEES FEOM THE POST-(iLACIAL OP ILLINOIS. 31 



cells, the abuudance and form of the markings ou the vessels, and the number and size 

 of the medullary rays. These dillerenccs are such as to render exact identification with 

 modern species hardly probable, and as a suitable means of distinction and recoguition 

 I would therefore propose for this fossil the name of Qiœnns marq/nna. 



Picea. — The wood of the Picea was cut with as great facility as the oak, and while 

 the transverse sections were quite clear as to the details of structure, the longitudinal 

 sections also gave numeruus well preserved details, from which a scries of drawings 

 (plate II) were prepared. 



So far as the details have been made out, they seem to establish affinity with Picea 

 silchensts, but as iu the case of the Quercus, the differences are such as to cause hesitation 

 in eftablishiug exact identity between them. Were it possible to establish identity 

 between the two, then there would be good evidence to show the extent to which the 

 area of distribution of Picea sitchensis has contracted within recent geological time, since 

 this species is now essentially confined to the Pacific coast, from Alaska to Mendocino, 

 California, extending inland not more than fifty miles. I deem it expedient to distinguish 

 this fossil by a separate name, for which I would suggest Picea evanstoni. 



Quercus marcyana, n. sp. 



Transverse section. Growth rings defined only by apposition of wood and vessels. No 

 obvious distinction of spring and autumn wood. Wood cells irregularly disposed, 

 the largest about 0.04 mm. in diameter. 



Vessels numerous and large, measuring about 0.20 X 0.30 mm. compressed tangen- 

 tially, chiefly in zones, alternating with zones of wood of about the same width. 

 Thyloses conspicuous. The larger medullary rays are about 0.24 mm. broad, and 

 usually separated by about twenty narrow rays of one cell in width. 



Radial section. Markings of the vessels obscure, owing to the operation of decay. 

 Thyloses conspicuous and abundant, and showing few round pits. 

 Medullary rays well developed ; cells short, usually once or twice as long as broad ; 

 walls rather thick and irregular, with numerous small channels ; ends square or 

 somewhat oblicjue. Perforations on the radial walls round, conspicuous and some- 

 what numerous. 



Tangential section. Thyloses conspiciious, the markings numerous and composed of narrow 

 slits. Markings on the walls of the vessels somewhat conspicuous and composed 

 of linear or narrowly elliptical slits. 



The smaller rays usually one row of cells wide, few to many cells high. The larger 

 rays are many cells broad and very''high. 



Picea evanstoni, n. sp. 



Plates II and III. 



Annual rings well defined ; tracheids of the autumn wood rather thick walled, of 

 the spring wood thin walled, with a single row of unequally disposed bordered "pits. 



