Page:The Journal of geology (IA journalofgeology21894univers).pdf/190

correlation of the New Jersey greensands, but does not attempt to separate the individual members of the series beyond the reference of the upper member to the Eocene, as was also done by the writer^[1] in his report upon the Eocene. It is impossible however, to satisfactorily correlate this upper member of the greensand series with the Eocene elsewhere, and it is not known how much of that horizon is included in it. It has been generally thought to represent the Lower Eocene of other regions. Concerning the other formations of the greensand series there seems to be little doubt of their reference to the Upper Cretaceous, although they probably do not include its earlier portions. Many of the same species have been found in the Cretaceous areas of the South Atlantic and Gulf States. Stanton^[2] has recognized thirty-five species as identical in Alabama, eighty-six in Mississippi, and fifty-four in Texas. Some of the species which are very much restricted in the New Jersey area, appear to have a greater vertical range in the Gulf region. It is therefore very difficult to delimit equivalent horizons. It is not unlikely that a fuller knowledge of the formations may render it possible to make more detailed correlations, but at present it is impossible.

On these grounds, therefore, an independent classification of the New Jersey deposits is demanded. The objections to the use of lithologic terms have been already cited, as well as the grounds for employing the place names adopted.

The greensand strata of New Jersey constitute a conformable series of beds aggregating nearly 550 feet in thickness. During the Matawan epoch, when fully one-half of these deposits were being laid down, land-derived materials reached the sea in large amounts, frequently interfering with the formations of glauconite, which is much less prominent at this horizon than later. During the succeeding epochs the production of greensand was much