INTRODUCTION. 13 



Coming now to the Laurinece, I have to remark somewhat more def- 

 initely on the Cretaceous species referred to this family. The relation of 

 some of them to the genera to which they have been referred is generally 

 acknowledged, and the presence of the Laurinece in our Cretaceous Flora 

 receives a kind of historical authority from that of a Sassafras in a Creta- 

 ceous formation of Greenland, 1 of three species of Daphnophyllum in that 

 of Moletein, and of Laurus cretacea, Daphnogene primigenia, Daphnites 

 Gopperti, in that of Niedershoena. Of the species which have formerly 

 been described in the Flora of the Dakota Group, Laurus Nebrascensis is 

 related to Daphnophyllum ellipticum and D. crassinervium of Heer, while 

 Cinnamomum and Oreodaphne cretacea are comparable to Daphnogene prim- 

 igenia of Ettingshausen. Persea Sternbergii is also evidently of the same 

 family, and the two leaves, described here below under the name of 

 Laurus protecefolia, are, indeed, allied to species of Laurus or of Persea by 

 their nervation, especially by the more acute angle of divergence of the 

 lower veins, though they show in the grooved middle nerve a character 

 often remarked in species of Ficus, especially Ficus protogcea, Heer, of the 

 Greenland Cretaceous Flora. Moreover, the fruit described ("Cret. Fl.," 

 p. 74) as Laurus macrocarpa satisfactorily completes the evidence afforded 

 by the leaves of the existence of species of Laurinece in the vegetable world 

 of the Cretaceous epoch. We have, however, to eliminate from this family 

 Laurophyllum reticulatum, which appears more properly referable to Ficus. 

 Its nervation, and especially its areolation, formed of square or irregularly 

 polygonal meshes by the interposition of tertiary veins between the second- 

 ary ones and parallel to them, and the rectangular subdivision of its 

 branches, are of the same character as in Ficus Geinitzi, Ett., Ficus protogcea, 

 Heer, and as in many species of this genus now growing in Cuba, and 

 even Florida, Ficus suffocans, F. lentiginosa, F. pertusa, F. dimidiata, etc. 

 Numerous specimens recently found in Kansas represent the fossil species 

 in characters more precise than formerly, as seen in its more detailed 

 description under the name of Ficus laurophyllum. 



But if the reference of some of the above-mentioned leaves to the 

 Laurinece is not contested, it is not the same in regard to those which, at 



1 In " Arct. Fl," vol. vi, 2d part, pp. 75-78, Heer describes as new species Laurus plutonia, L. angusta, 

 L. Solla, L. Odini, with Cinnamomum Sezannense, Wat., from the Upper Strata of Atane. 



