438 W. B. Clark — The Matawan Formation. 



basin of Potomac sedimentation. It is possible that the Island 

 Series of Professor Ward farther north may also prove to be 

 the equivalent of these beds, although the exact stratigraphic 

 limits of the former are not quite clear. 



Uhler* in 1892 described what he termed the "Alternate 

 Clay Sands" overlying his Albirupean (in part Raritan) forma- 

 tion in Maryland, and Darton f in 1893 proposed the name 

 Magothy formation for these deposits, stating that they con- 

 stituted a well-defined stratigraphic unit between the Potomac 

 formation below and the marine Cretaceous deposits (Matawan, 

 etc.) above. He, as well as Shattuck,J regarded certain of the 

 clays, which unquestionably underlie the true Matawan forma- 

 tion, as part of the Matawan, and the similarity of the materials 

 would often suggest this reference. Recent work by the 

 writer and his associates both in Maryland and in New Jersey, 

 as well as along the Delaware and Chesapeake Canal§ in 

 Delaware, shows that a series of deposits, lying between the 

 Matawan above and typical Raritan below and consisting of 

 alternating beds of dark clays and light sands, the latter fre- 

 quently brown in color, or of one or the other, as the case may 

 be, and having a thickness of from 10 to 100 feet or more, can 

 be traced almost continuously from the western shores of the 

 Chesapeake Bay in Maryland to the Raritan Bay in New Jersey. 

 Darton was evidently the first to name this formation should it 

 be ultimately shown to represent a single stratigraphic unit. 

 In the absence of satisfactory exposures in Maryland a critical 

 study of the plant remains is demanded before final judgment 

 can be passed. It is highly probable, however, that the Mary- 

 land strata represent a somewhat lower horizon than the fossil- 

 iferous beds at Cliffwood, and may be the equivalent, in part 

 at least, of the "laminated sands" which underlie the lignitic 

 beds at Cliffwood. The base of Darton's Magothy may thus 

 prove to be the base of the " laminated sands " and may neces- 

 sitate the transfer everywhere of certain upper sands hitherto 

 regarded as Raritan to the Magothy-Cliffwood series. 



The Matawan formation in New Jersey, as previously stated, 

 has been divided by the author into the Cross wicks clays and 

 Hazlet sands, the former corresponding to the Merchantville 

 clay and the Woodbury clay and the latter to the Columbus 



*Uhler, P. R., Trans. Md. Acad. Sci., voi. i, pp. 200, 201, 1892. 



f Darton, N. H., this Journal, ser. iii, vol. xlv, pp. 407-419, 1893. 



JShattuck, G. B., Md. Geol. Survey, Cecil County Report, pp. 158, 159, 

 1902. 



§ The section in the Deep Cut of the Delaware and Chesapeake Canal is 

 one of the best in the Coastal Plain and shows the Matawan resting on the 

 clays and sands of the Magothy formation, which at this point are in places 

 highly lignitic. The Matawan formation consists at the base of chocolate- 

 colored marls 15 to 20 feet in thickness overlain by black micaceous sandy 

 clays 10 to 12 feet in thickness, which together apparently represent the 

 Crosswicks clays. Above these beds is a more sandy member distinctly 

 glauconitic that may perhaps represent the Hazlet sands farther north. At 

 the eastern end of the Deep Cut the red sands of the Monmouth occur with 

 fossils characteristic of the lower Monmouth in New Jersey. 



