422 



SCIENCE. 



[N. S. Vol. V. No. 115. 



this is not all. The Shasta group, at least, 

 is directly underlain by true Jurassic beds. 

 It is altogether improbable that those who 

 have established the age of these deposits 

 from what is admitted to be the very best 

 paleontological evidence will abandon this 

 determination and adopt that of Professor 

 Marsh. 



When I made my slight contribution to 

 this discussion* only Professor Marsh's two 

 papers on the ' Geology of Block Island ' 

 had appeared, in which the evidence to es- 

 tablish his position was promised in the fu- 

 ture. From the confident manner in which 

 he spoke in those papers all expected that 

 his next paper would contain an account of 

 the discover}' of Dinosaurs and other verte- 

 brate remains on Block Island, Long Island, 

 Staten Island, and Marthas Vineyard. His 

 much fuller paper in the December number 

 of the American Journal of Science is disap- 

 pointing in not furnishing this evidence. 

 Every one, I believe, would welcome any 

 facts bearing on the subject, and all are 

 equally interested in considering all possi- 

 ble data. His failure to present such evi- 

 dence in this paper leads some skeptical 

 people to suppose that it does not exist. 

 Speaking of Gay Head, he says (p. 437): 

 " The striking resemblance between the va- 

 riegated cliflFs at Gay Head, the Potomac 

 hills in Maryland, and Como bluffs in Wy- 

 oming, will impress everj'one who has seen 

 them. That all three are of essentially the 

 same geological age, I have good reason to 

 believe. Two of them are certainly Juras- 

 sic, as demonstrated by typical vertebrate 

 fossils, and / hope soon to protie that Gay 

 Head, so similar in all other respects, also 

 contains the same characteristic vertebrate 

 fauna that marks the Jurassic, — the long 

 missing formation on the Atlantic coast." 



It would have been much better if he had 

 actually proved this. It is always unsafe 

 in geology to predict what we shall prove; 



*SciENCE, N. S., Vol. IV., Nov. 20, 1896, p. 757. 



such sweeping generalizations as Professor 

 Marsh makes are very hazardous. To stand 

 on Block Island and correlate its formation 

 with that of Como bluffs in Wyoming is 

 not the modern method of geological in- 

 vestigation. As he says: " The Gay Head 

 Indians are not hostile." I did not find 

 them so, neither did Mr. White when he 

 made his large collection of fossil plants 

 there. They would probably not harm a 

 vertebrate paleontologist any more than a 

 paleobotanist, and I submit that there is a 

 better way of geologizing than to sit at 

 one's ' studj' window ' at New Haven and 

 ' look across the Sound to Long Island.' 



It is still fashionable to disparage the 

 evidence from fossil plants, and Professor 

 Marsh's papers would have been incomplete 

 without the usual amount of this kind of 

 matter. This is not the place to enter into 

 a defense of fossil plants or to point out 

 their value to geology. I have attempted to 

 do this on former occasions.* I only desire 

 here to refer to the two authors whose works 

 I have considered as among those who do 

 not take this view. Professor Marsh has 

 followed most other writers in digging up 

 the errors of the early paleobotanists while 

 ignoring the work of the later ones, but I 

 am surprised that he should have adopted 

 the view which resulted from these errors, 

 and which has long been exploded, that 

 there is any lack of harmony between the 

 evidence which plants afford and that of 

 other forms of extinct life. Dr. Newberry 

 was one of the first to correct this error and 

 to insist that when all the evidence from 

 plants and animals should be in there would 



* Principles and Methods of Geologic Correlation 

 by Means of Fossil Plants. American Geologist, 

 Vol. IX., pp. 34-47; Principes et methodes d'etude 

 de correlation geologique an moyen des plantes fos- 

 siles, Conipte-rendu de la cinquieme session du 

 Congres gi'ologique international, Washington, 189], 

 pp. 97-109. Cf. also: Fossil Plants as an aid to 

 Geology, by F. H. Knowlton, Journal of Geology, 

 Vol. 11., pp. 365-382. 



