JEFFRKY. — AR.VUCARIOXYLON TYPK. OoS 



extend rows of wound resin cjiiiiUs. Fjirther out tlicsc dis;ii)[)ear 

 entirely as is wont to be the case in woods, giving' rise to cjinals of 

 this type, unless the injury is extremely severe. The eanals are in 

 some eases obviously very wide in the tangential plane. This feature 

 indicates their lateral fusion with one another, a condition quite typi- 

 cally present in traumatic resin-canals. The canals are surrounded 

 by cells filled with very dark contents, wdiich sometimes makes its 

 way into the lumen of the canal itself. The rays are likewise occupied 

 by a dense dark hued substance. Figure e, Plate 7, shows the canals 

 in longitudinal radial section. They are clearly not of equal caliber 

 throughout as is usually the condition in Pinus, but are constricted 

 at intervals even in the short portion shown in the figure. This 

 condition is likewise one, which is characteristic of traumatic resin 

 canals, although it is also more or less observable in the normal canals 

 of the wood in the Al)ietineous genera, Picea, Pseudotsuga and Larix. 

 To the right and left of the resin canal are metluUary rays. The 

 magnification is not sufficient to show their structure, which will be 

 figured in detail subsequently. It is enough to state that the rays in 

 this region of the wood are very strongly pitted, exactly as in Arau- 

 cariopitys described abo\e. The pitting is Araucarian of the Brachy- 

 oxylon type, that is the pits are not only flattened or alternating but 

 also occur in the rounded and well spaced condition characteristic of 

 the Conifers, other than the Araucarian tribe. Bars of Sanio cannot 

 be made out in the wood under consideration or in any similar ones 

 from the same deposits. 



It is clear from the foregoing paragraph that there are woods in 

 the Jurassic, which as regards their features of organization combine 

 Abietineous and Araucarian characteristics. They have namely the 

 strongly pitted rays and traumatic resin canals of the Abietineae, 

 combined with the pitting of the tracheids and the absence of bars 

 of Sanio which are recognized, by those who have made a special 

 studj' of Araucarian woods, as diagnostic of the Araucarian tribe. 

 There are obviously two possible interpretations of the combination 

 of characters referred to above. It is agreed by competent investi- 

 gators that the features under discussion clearly indicate a close 

 degree of relationship in the Jurassic, between the Abietineous and 

 Araucarian tribes. The disagreement, however, arises as to whether 

 the Abietineae have come from the Araucariineae or the opposite 

 mode of derivation is the correct one. Gothan in the two important 

 memoirs on the Jurassic woods of King Carl's Land and Spitzbergen 

 cited above, takes the view that the transition is from the Araucarian 



