436 W. B. Clark — The Matawan Formation. 



introduced. With the extension of the work southward from 

 Monmouth County, and more particularly with the study of 

 the stratigraphy in Maryland, we soon came to the conclusion 

 that the reddish brown sands (Mt. Laurel sands, called Weno- 

 nah sand by the New Jersey Geological Survey) beneath the 

 Lower Marl bed (Navesink marls) properly belonged with the 

 Navesink marls and Redbank sands above rather than with the 

 Matawan below. The Redbank sands were found to disappear 

 in about the latitude of Philadelphia, bringing the Navesink 

 marls in Camden, Gloucester, and Salem counties, New Jersey, 

 into immediate contact with the Rancocas marls above, from 

 which, however, they can be separated by their contained fos- 

 sils and by their more or less distinctive materials. The 

 Monmouth formation was established to embrace the three 

 beds.* In Maryland, however, no such differentiation of the 

 Monmouth is discernible, the only deposits found between 

 the Matawan formation below and the Rancocas formation 

 above being more or less homogeneous red sands, glauconitic 

 from base to top. Earlier attempts to maintain the New Jersey 

 subdivisions in Maryland have not proven satisfactory. \ A 

 proper division of the Cretaceous deposits would therefore call 

 for a drawing of the line between the Matawan and Monmouth 

 formations below rather than above the Mt. Laurel sands. 



A lens of clays and interbedded sands lying beneath the 

 typical Matawan at Cliff wood, New Jersey, on the shores of 

 the Raritan Bay, and included by the w T riter in that formation 

 in his " Preliminary Geological Map of portions of Monmouth 

 and Middlesex counties, New Jersey," accompanying the report 

 of the State Geologist for 1892, has been the subject of much 

 discussion of late, although none of the views thus far advanced 

 seem to afford an adequate explanation of the conditions there 

 presented. The clays, which are more or less micaceous and at 

 times sandy, possess many features in common with the typical 

 Matawan deposits above, even to the occurrence now and then of 

 patches of glauconite.;}: The interbedded sands, as well as the 

 lack of continuity of the clay beds, suggest, on the other hand, 

 conditions characteristic of the Raritan, although the deposits 

 as a whole show quite marked differences from the typical 



*Bull. Geol. Soc. Amer., vol. viii, pp. 315-358, 1897. 



f The idea has been advanced that the Maryland Monmouth may perhaps 

 represent the Mt. Laurel sands alone, and that the Navesink marls along with 

 the Redbank sands have disappeared in Maryland, but the long distance 

 between the last outcrop in New Jersey and the first occurrence on the west 

 side of the Delaware Bay renders it unwise to draw such a conclusion from 

 the data now at hand. The deposits have furnished, to be sure, specimens of 

 Belemnitella ainericana, which is a distinctly lower Monmouth form farther 

 north, but as they did not come from the higher beds of the Delaware- 

 Maryland strata tho evidence is not conclusive. 



JMr. E. W. Berry, on a recent visit to the locality, removed a small envelope 

 full of glauconitic material from one of these patches below the debatable 

 contact of the Matawan. The writer has also found glauconite in these beds, 

 although the patches are very infrequent. 



