1914] HOLDEN— CRETACEOUS LIGNITES 169 



instances of the first may be mentioned the occurrence of resin 

 canals in the center of the root of such conifers as Abies and Tsuga. 

 a harking back to the time when they were scattered throughout 

 the wood, as in Finns; as instances of the second, the presence of 

 centripetal wood in the cone axis of Equisetum; and of the last, the 

 ray tracheids in wounded specimens of Abies. It seems clear, 

 therefore, from comparative anatomical and developmental evi- 

 dence, that the Araucarineae are descended from ancestors which 

 had thick-walled pitted rays, wood parenchyma, and scattered 

 tracheary pits separated by bars of Sanio. These hypothetical 

 ancestors are probably the Abietineae. 



If such a conclusion is correct, we should expect to find fossil 

 record of woods which possessed these modified araucarian struc- 

 tures, not only in primitive places, but also in their normal, mature 

 growth. Recent investigation has shown such to be the case. 

 For example, Araucarioxylon Lindleyi Seward, Cormaraucarioxylon 

 crasseradiatum Lignier, and Araucarioxylon noveboracense Jeffrey 

 have wood parenchyma; Cormaraucarioxylon crasseradiatum Lig- 

 nier, Protocedroxylon araucarioides Gothan, and Araucariopitys 

 americana Jeffrey have thick-walled pitted rays. Further, many 

 of these Mesozoic araucarians have traumatic resin canals, as do 

 Abies, Cedrus, etc. Up to the present, however, no fossil araucarian 

 has been described with opposite pits or bars of Sanio. In an 

 earlier paper 3 the writer has described several species of Pityoxylon 

 from the Raritan Cretaceous of Ciiffwood, New Jersey. These 

 were included in a considerable amount of lignite collected by Pro- 

 fessor Jeffrey, and turned over to the writer for investigation. 

 In addition to the Pityoxyla, there were a number of Cupressinoxyla, 

 and one Araucarioxylon. This last specimen was of especial inter- 

 est in this connection, and will accordingly be described first. 



The material consisted of a flattened stem about two inches in 

 length and one in diameter. The preservation of the outer layer 

 was but indifferent; near the center, however, it was excellent. 

 The pith contains large masses of stone cells, similar to those of the 

 living Agathis. Fig. 1 represents a radial section of the wood at 



3 Holden. Rith, Cretaceous Pityoxyla from Cliffwood, New Jersey. Proc. 

 Amer. Acad. 48:609-623. ph. 4. 1913. 



