COPE.] PALEONTOLOGY CRETACEOUS PERIOD AGE. 443 



'Since the above was written, a paper* by Prof. J. S. Newberry has 

 appeared, in which he gives full expression of his views as to the ages 

 of the different extinct floras of the West. He points out clearly that 

 the tiora of the Fort Union beds is part of that which is extensively 

 distributed over the northern hemisphere, and which is believed to char- 

 acterize the Miocene period in Europe. He states that characteristic 

 structural parallelism between American and European plants does not 

 obtain iu tlie preceding f)erio<ls of the Eocene and Cretaceous, aud. that 

 the flora found in the lower part of our Cretaceous formations, as deter- 

 mined by animal remains, is " somewhat more closely allied to the Ter- 

 tiary flora than are the plants found in. the Cretaceous of Europe." He 

 does not make any botanical determination of the age of the fossil 

 plants of the Bitter Creek series, nor of the lignite beds of Colorado. 

 He, however, objects to regarding any of the floras found below the Fort 

 Union foruiation as Tertiary in the following language, (p. 402:) "The 

 lignites and plant- beds of ]Sew Mexico, which I have called Cretaceous, 

 but which are referred by Mr. Lesquereux to the Tertiary, are, for the 

 most part, derived from thfe lower portions of our Cretaceous series, and 

 are overlaid by many hundred feet of strata unquestionably Cretaceous, 

 in which all the typical forms of Cretaceous animal life are abundantly 

 represented. Whether the great lignite deposits of Colorado should be 

 considered Tertiary or Cretaceous, it is perhaps not yet possible to 

 decide ; but in the absence of any distinctive or unmistakable Eocene 

 plants, if the strata which contain them shall be found to include verte- 

 brates or mollusks which have a decidedly Mesozoic character, we shall 

 be compelled to include them in the Cretaceous system. Mr. Lesque- 

 reux has met the statements of Professors Meek, Co[>e, and Marsh by 

 pointing to his two hundred and fifty species of fossil plants, claiming 

 that they far outweigh the testimony of the animal remains. In fact, 

 however, these fossil plants have very little bearing on the question. 

 They are probably all distinct from European Cretaceous and Eocene 

 species, and the genera to which they are supposed to belong afford 

 only negative evidence of the strata that contain them." 



Thus it is evident that Professor Newberry appeals to the evidence 

 furnished by the animal remains as basis of determination of the epochal 

 type of the contemporary vegetable life. In further illustration of his 

 vif'w he says, (p. 404:) "Whatever plants are found with Zeuglodon 

 cetoides, Cardita planicosta, Orhitoides mantelUi, &c., we must accept 

 as Eocene, even should they have no intrinsic Eocene characteristic. 

 So in regard to our Cretaceous flora. While it is altogether new, its 

 varied character and modern aspect simply give us a new revelation in 

 regard to the vegetation of the Cretaceous world ; for, while the fauna of 

 that world contains Ammonites, Baculites, Inoceramus, &c., we are forced 

 to call it Cretaceous." 



It certainly appears to me to be introducing a new element into pale- 

 ontological reasoning to estimate the age of one class of fossils by refer- 

 ence to the structural characters of another. Every flora and fauna, and 

 every genus in them, offers its own intrinsic evidence as to age or relation 

 to other genera of preceding, contemporary, and succeeding time ; and 

 all that we can affirm of the relations of the life of any given deposit 

 or age are the sums or results of the various parts of such flora and 

 fauna. In the present case, the evidence brought forward by Dr. New- 

 berry from his own stand-point as a distinguished student of extinct veg- 

 etation, and upon which I necessarily rely, is : (1.) That the floras of the 



* American Jourual of Science and Arts, 1874, j). 399. 



