330 GEOLOGICAL SURVEY OF THE TEERITOEIES. 



fig. 2, we have another character which presents the union of leaves 

 of this kind either with the Laurinece or with the Araliacea, and thus it 

 is necessary to admit a third generic division for the chissification of the 

 vegetable remains of this new and remarkable type, which adds to its 

 affinity to Sassafras and Aralia a character which relates it to Platanus 

 and Credneria, by the basilar appendage of the leaves and its nerva- 

 tion. We have thus already in those leaves Sassafras, represented by 

 iS. Mudgei, and less positively by 8. acutilobum, S. cretaceum, and 8. 

 cretaceiim var. obtnstwi, which, as seen by the description, has to be 

 considered as a specific form. To Arcdiopsis are referable 8. mirabile, 

 with the dentate 8. cretaceum and Platanus recurvata; and to the 

 new generic divisiou, under the name of Aspidiophyllum, those leaves 

 which, either Ariilia or Sassafras by their upper trilobate part, are 

 forcibly separated from these genera by their auricled peltate append- 

 age. Still, the subdivisions in the classification of these peculiar and 

 so-called Sassafras leaves, have to be pursued farther, for by degree and 

 by the gradual obliteration of their lobes, they become round or truncate, 

 or broadly pointed at the top, preserving more or less the narrowed base, 

 tapering to a long petiole, and the trilid craspedodrome nervation from 

 a distance above the borders, and thus they become more evidently 

 rehited to other vegetable orders. One species is a true Hedera, 

 another goes to the Hamamelidew, and a number have their affinity 

 with the Ampelidece. 



The characters of the leaves of this order, especially those of Cis- 

 sns, are somewhat obscurely represented in 8assafras Harlcerianum, 

 Cret. Flor., PI. XT, figs. 3 and 4; PI. XXVII, fig. 2, and in 8. 

 oMusum, PI. XIII, figs. 2 to 4; more distinctly in Cissites actiminatus, 

 PI. VIII, fig. 1 ; and (7, Heerii, PI. VI, fig. 3, two new species de- 

 scribed in this memoir. They appear to constitute an indivisible 

 group with the two former ones. Some of the leaves formerly de- 

 scribed as Populites are also referable to this section, or to another 

 less exactly defined ; Ampelophylluni, allied by some of its characters 

 to Hedera, by others to Credneria ; thus intermediate to the Ampelidce 

 or the Tiliacece; by the areolation to Greviopsis, and also more distantly 

 to Chondrophyllum of Heer, as remarked in the description. From this 

 it is perceivable that this Sassafras type, which at the beginning 

 was regarded as simple, well defined, and limited in its character, is, on 

 the contrary, multiple and representing forms which, as far as the re- 

 searches increase the discoveries, indicate affinity to a number of differ- 

 ent genera or orders of the vegetable reign. Considering for example 

 8assafras acutifoUum of Cret. Flor., PI. XIV, which, from specimens 

 representing intermediate forms between fig. 3 and fig. 4, 1 was disposed 

 to consider as a mere variety of ;S^. 31udgei, and passing to fig. 7 of PI. 

 XXX, evidently of the same generic type, and then to fig. 1 of PL VIII 

 of this memoir, where is the difference or the point of separation to be 

 marked ? The type of Ampelidce is quite as distinct as that of the 

 Araliacew in this peculiar group ; but both are recognized it seems 

 merely in the extreme and opposed limits of their modifications. 



The same remark is applicable just as well to the leaves which have 

 been described in the Cret. Flora under the generic name of Frotophyl- 

 lum. The disagreement in the affinities of its species has been exposed 

 in the remarks following the description of the genus. I have now to 

 add still to this division two leaves recently communicated from Kan- 

 sas, represented, PI. Ill, fig. 1, and PI. VIII, fig. 4. Thej^ fnlly confirm 

 the former observations. By the outline of the leaves, their craspedo- 

 drome nervation, and the presence of two pairs of secondary veins 



