12 INTRODUCTION 



than 12-20 miles north of the Beacon Hill formation. At the 

 final recession of the ice there is some evidence of another slight 

 subsidence of the lower part of the state and the coastal region, 

 but not enough to have brought the Beacon Hill formation any- 

 where near down to sea level. This last subsidence of the coastal 

 strip and the Cape May region had a significant influence upon the 

 distribution of the plants of the area. It seems very probable 

 that a gradual sinking of this region has been going on ever since, 

 as the sea has constantly encroached upon the land throughout 

 maritime New Jersey, as indeed it has in Staten Island, Long 

 Island, and further north. 



24. Whether one follows Johnson* in believing that this sub- 

 sidence of the coastal part of our area is not recent or continuing 

 or Bartlettf that it is both recent and continuing, does not matter 

 so much for our present purposes. Both agree, and the evidence 

 is of such a nature that it appears incontestable, that there was a 

 great deal of ancient subsidence. In Cape May County this has 

 been of such an extent that whole regions covered by forests of 

 white cedar (Chamaecyparis thyoides) have been submerged, 

 emerged, and submerged again. This, repeated several times, has 

 resulted in a great accumulation of buried forests. "Trunks of 

 trees are found buried at all depths beneath the surface, quite down 

 to the gravel."J This and "numerous facts of the same kind 

 . . . collected along the shores of the Delaware Bay and River, in 

 Salem and Cumberland Counties, and on the sea-shore in Atlantic, 

 Ocean, Monmouth, and Middlesex Counties," all seem to point to 

 a decided ancient submergence of the area surrounding the Beacon 

 Hill formation. 



25. So much for a brief outline of the geological sequence of 

 events in the pine-barren area. For the phytogeographer, the 

 salient features of these changes are that Beacon Hill has been 

 uninterruptedly out of the water since upper Miocene times, and 

 that it has several times been partly, and often entirely surrounded 

 by water. These facts, together with the encroachment of the 

 glacier, and its recession, with the probable deposition of a great 



* Johnson, D. W. Botanical evidence of coastal subsidence. Science II. 37: 721 

 1910. Science II. 38: 300. 1911. See also Bot. Gaz. 54: 449-468. 1913. 

 t Bartlett, H. II. Science II. 38: 300. I < J I I . 

 | Geology of the county of (ape May 62 and 39. 



