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scending direction, the smaller will necessarily have a more or less 

 furrowed aspect on the lower as well as on the upper half of the 

 great scar. 



It is remarkable that among the many specimens of Ulodendron 

 that have been seen, none have exhibited the appendicular organ 

 in its natural relation to the stem. Dr. Hooker says, Mr. Dawes 

 showed him a specimen preserved in. sandstone, with a large organ, 

 which he considered to be a cone inserted into one of the cup-shaped 

 dej)ressions ; but he was unable to form any conclusion concerning 

 its real nature.* Had Prmcipal Dawson rested his determination 

 that scars were the impressions of the bases of cones on his having 

 found one in situ, I must have concluded that his plant was very 

 different from the European Ulodendron; but his illustration t agrees 

 with the scars we have figured and described. We hope that a re- 

 examination of the matter in the light of the additional facts and 

 explanations contained in this paper, may lead the learned author to 

 a different interpretation of the structure. 



That the appendages were articulated to the stem by the whole 

 surface of the scar cannot be doubted. In the want, however, of 

 any observed specimen, it is not so easy to determine what these 

 appendages were. The specimen figured on Plate XLIII., Fig. 5, 

 appears to me to throw considerable light on the matter. In this 

 species the opposite series of scars are borne on swelhngs on the 

 stem, and the downward aspect of the scars shows that the organs 

 which sprang from them had a descending direction. That this is 

 the true position of the stem is abundantly established by the dark 

 carbonaceous patches which here and there are attached to it, and 

 which are the bases of the leaves converted into coal. One of these 

 patches from the other side of the stem from that shown in the 

 drawing is represented the size of nature at Fig. 6, and here it is 

 seen that the bases of the leaves still remaining are imbricated 

 over each other, and that the scars where the leaves were broken 

 off are on the upper portion of each base. This clearly shows the 

 natural direction of the specimen figured. The appendages, then, 

 must have been adventitious roots in this specimen. In the light 

 of this specimen, the form and direction of the scars where their 

 original dej)th is to any extent preserved, appear to corroborate this 

 view. The aj)pendage could not in any of them have been patent ; 

 indeed, they seem to show that it must have passed out outwards 

 and downwards. 



The scars are not at all constant in the method of their arrange- 

 ment. In U. iMrmatum I have seen a considerable fragment of 

 the stem with only one well-formed scar upon it, the remainder 

 being covered with rhomboidal leaf scars ; in other specimens I 

 have observed from eight to twelve scars, so closely aj^proximated in 



* ' Memoirs Gcol. ISurv. Great Brit.,' vol. ii., pi. ii., p. 427. 

 t ' Actiiliaii Geology,' p. 457, llg. 170. 



