D. White — Oretaeeatu Plant* from Martha's Vineyard. ( . ,( .> 



the remains of gum or oil vessels, Buch as exist in the nuts of 

 recent Encalypts; and the granules of "amber" can hardly 

 be else than Eucalyptus gum. 



The explanation IS at once suggested that the fragments of, 

 amber observed by various writers, during the last hundred 

 vear-. about Gray Head, and in the New Jersey Cretaceous, 

 where also Encalypts are found, are the product of the con- 

 temporaneous "gum-tn rather than of some conifer. 

 ue of this American amber has, I believe, been tested for 

 succinic acid, or to show its relation to true amber. 



Although the tertiary nervation of the figured specimen of 

 indus, tig. 12, is wanting, 1 have little doubt, after com- 

 paring it with the figures by Lesquereux and lleer, that it is 

 referable to S. Morrisoni Lx\, from the Dakota group of Ne- 

 braska, Lower Atane beds (Middle Cretaceous), and from the 

 Patoot beds (Upper Cretaceous) of Greenland. 



A- was remarked above, a large part of the Gay Head spe- 

 cies aeems to be as yet undescribed. Of the remainder, all the 

 identified species are found in the Cretaceous, and all but 

 gn viMioides Hr. were present in the Middle Cre- 

 taceous. The relation of the Gay Head flora with that of the 

 Middle Cretaceous (Cenomanian) of Greenland seems nearer 

 than that with the flora of the Dakota group. There is, how- 

 ever, every reason for believing that it will be found to be 

 very largely identical with the flora of the Amboy clays, from 

 which, unfortunately, only six species have as yet been pub- 

 lished. It is hoped that Dr Newberry's forthcoming mono- 

 graph of that rich flora will soon appear. 



The evidence, then, of the fossil plants bespeaks an age that 

 is decidedly Cretaceous, and probably Middle Cretaceous, for 

 the terrane in which they were deposited. 



The question which was raised in the case of the Cretaceous 

 invertebrates will doubtless be repeated as to the plants, viz : 

 whether the immediate matrix in which the plants are found is 

 not either transported and re-imbedded rock, rather than of the 

 nature of true concretions ; or whether, supposing the concre- 

 tions to be genuine, they may not have existed as such in the 

 older formations whence that part of the Gay Head sediment 



- derived. The circumstances which unite to prove that the 

 plants lie in their original matrix and terrane are as follows: 

 Tiie plant-bearing concretions, which are generally more or less 

 lenticular or oblong-lenticular, sometimes geodic or columnar 

 within, show, often clearly, the concentricity of their structure. 

 In many cases they are formed about a stem-fragment of quite 

 large size. Some are concreted about balls of clay or sand. 

 The leaves, which are often thickly matted, may occur in any 

 zone, and are usually parallel to the longer axes of the concre- 



