418 



SCmNCE. 



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



have been found in the moraine on the 

 extreme end of Montauk Point. Farther 

 east, the clay series reappears on Marthas 

 Vinej'ard and forms part of the noted cliff 

 of Gay Head." 



It is therefore clear that he includes in 

 his Amboy Clays all the deposits north of 

 the Delaware Eiver, and that so far as these 

 deposits are concerned they are the same as 

 those to which Professor Marsh has referred 

 in this section of the belt. As regards 

 points farther south he has also made him- 

 self tolerably clear by the following lan- 

 guage (p. 22): 



" The southern extension of the formation 

 has not been definitely traced, but it ap- 

 parently thins out southward, appearing as 

 an insignificant element in the series in 

 Cecil county, Md., where Professor Uhler 

 has described it as the bed of ' alternate 

 sands and clays ' which there rests on the 

 Potomac and is overlain by the equivalents 

 of the Cretaceous marl beds of New Jersey. 

 South of this point it has not been recog- 

 nized." 



That Dr. Newberry found no close rela- 

 tions between the Amboy Clays and the 

 Trias is also evident from the summary 

 manner in which he dismisses this whole 

 subject (p. 22): 



" In New Jersey the Amboy Clay series 

 is generally underlain by the Triassic red 

 sandstones, which have been proved to be 

 of the age of the Keuper or Upper Trias in 

 Europe." 



As to the real age of the Amboy Clays 

 his opinions are so important that they 

 need to be stated in full. After referring 

 to the animal remains, in which he makes 

 use of the same data as were employed by 

 Professor Marsh, viz., the report of Professor 

 R. P. Whitfield, he says (pp. 22-23): 



" This evidence shows that the New 

 Jersey clays occupy a position lower than 

 the European chalk and higher than the 

 upper member of the Trias. Such other evi- 



dence as can be gained in regard to their precise 

 geological age must he derived from their abundant 

 plant remains, ^mong which are a number of 

 species that are common to the Dakota 

 sandstones of the interior of the continent, 

 to the Atane and Patoot beds of Greenland 

 — known to be Upper Cretaceous — to the 

 Cretaceous clays of Aachen, Germany, and 

 to the Upper Cretaceous rocks of Bohemia." 



Turning then to the Older Potomac he 

 discusses its relations to the Amboy Clays 

 as follows (p. 23): 



" The i-elation of the Amboy Clays to the 

 Potomac formation of Virginia is not easily 

 demonstrated, as the line of junction has 

 not been fully traced, but we may say that 

 the Potomac is the more ancient formation, 

 and that probably a somewhat long interval 

 of time separated the epoch of the Potomac 

 group from that of the Amboy Clays. This is 

 indicated by the almost entire distinctness of 

 the floras of the tivo formations, which shows 

 that a great change took place during that in- 

 terval in the character of the vegetation which 

 clothed the eastern shore of North America. 

 Professor Fontaine has described, from the 

 Potomac group of Virginia and Maryland, 

 S65 species of plants, of which not one is cer- 

 tainly found in the Amboy Clays ; and the 

 difference in the character of the vegetation 

 is shown by the fact that in the long list fur- 

 nished \>y Professor Fontaine there are hut 

 7S angios'perms (about one-fifth of all) , 

 whereas in the New Jersey clays, throwing 

 out fragmentary and doubtful remains, of 

 156 described species all hut 10 are dicotyledon- 

 ous plants." 



Having thus disposed of the possibility 

 of the Potomac formation in Virginia being, 

 of the same age as the Amboy Clays, and 

 having demonstrated its much greater an- 

 tiquity, he sets about to discover the true 

 geological affinities of the Amboy Clays. 

 His conclusions maj' best be given in his 

 own words (pp. 23-24): 



" The relation of the Amboy Clays to the 



