1892] MARYLAND ACADEMY OF SCIENCES. 189 



beds, where undisturbed and in place, are leaves, branches, 

 wood, and seeds of plants and trees, of much more modern 

 type than those which occur in the undisturbed Potomac 

 clays. Wherever they are most compact and argillaceous, 

 little else than lignite, more or less coated or impregnated 

 with iron pyrites, is to be found imbedded in them. When, 

 however, they are laminated or foliated, the leaves of 

 many genera and species of Angiosperms are distributed 

 within the layers. 



These beds of black marl are not lenses ; the}' form thick, 

 long, and wide deposits in ridges and belts, which are dis- 

 coverable at various intervals between the Raritan bay 

 and the country south of Trenton. They extend from 

 Bordentown to Kincora, and are exposed at intervals near 

 the Delaware river. At Fish House they present exten- 

 sive deposits, and may be seen in deep cuts which extend 

 into the suburbs of Camden. 



In numerous places throughout western and central 

 New Jersey, but notably near Washington and Sayres- 

 ville, and from thence to South Amboy, and again from 

 the latter place to the hills east of Cheesquake creek, the 

 black clay marl forms the body of broad areas of high 

 rolling country. The more compact and plastic form of 

 it constitutes immense deposits, running deep below tide- 

 level in the high region west of South Amboy. 



These black clay marls must not be confused with the 

 dense l)lackish strata called '• Blue Clays " in the Wood- 

 bridge district. In that region the black marls occur in 

 beds at a much higher level than the " Blue Clays," and 

 wherever the Alternate Clay Sand series is well developed, 

 the black clay marls usually appear as the thickest mem- 

 ber. They do not always occupy the upper part of the 

 alternating group, since in certain exposures the sandy 

 layers are more numerous and have their greatest develop- 

 ment superiorly. In other cases the black marls have 



