COASTAL PLAIN CKKTACKOUS DEPOSITS. 48l 



and liis c<)lalH)ivry for the viihuiblc contributions which they are niiikin<r to our 

 knowledge of the fo:?sil phint^ of these fornuitions. 



MA TA WAS FOtiMA TIOS 



The Miitawan shows remarkable pereistence in l)oth its litholojjjical and paleonto- 

 logical characteristics. It consists of dark colored clays with interbedded layers of 

 sand, the former highly micaceous and at times glauconitic, the greensand, how- 

 ever, occurring in relatively thin beds and, for the most part, locally developed. 

 In this respect it dillei-s from the overlying formations, where the greensand is 

 evenly distributed, and from the Karitan, which lacks it altogether. The character 

 of the fossils indicates marine conditions and a profusion of molluscan life. Fos- 

 siliferous localities have been found at Keyport, Crosswicks, Pensauken and other 

 points in New Jersey along the line of strike and upon the Chesapeake and Dela- 

 ware canal, the Magothy river, the Severn river und at Millei-sville and Fort 

 Washington, in Maryland. Throughout this long distance are found the same 

 characteristic, dark micaceous, sandy clays and similar fauna. 



NA VESISK FORMA TIOS 



The Navesink, characterized by its highly glauconitic strata, extends from the 

 shores of Karitan bay with almost continuous outcrop across New Jersey. It is 

 profusely fossiliferous at numerous points and, with its large and well preserved 

 specimens of E.iotji/nt costata and Gri/pJiwa reticularis as well as the common Bdcin- 

 niU'lla (imrricana, is readily recognized. 



The Navesink formation outcrops in Delaware along the line of the Chesapeake 

 and Delaware canal, extending thence southeastward to the drainage of Big Bo- 

 hemia creek, ami beyond the Chesapeake appears certainly as far south as Seat 

 Pleasant, in Prince Georges county, where highly fossiliferous beds occur. It 

 probably has a wider distribution to the southward. In general the deposits are 

 less fossiliferous in Maryland than in New Jersey and the lithological distinctions 

 are also less sharply defined. 



RED BASK FORMATIOS 



The Redbank consists tyi)ically of red sands, more or less glaucronitic, althcjugh 

 the green grains of that mineral have been extensively altered on account of the 

 loo.se arenaceous i-haracter of most of the beds. The Redl)ank f(jrmation is a i)romi- 

 nent factor in the New Jei-sey series, where its bright red color is one of the most 

 striking features throughout the marl district. 



On the " Leister n shore" of Maryland, as at Bohemia mills, it i-etains most of its 

 northern characters, but south of the Chesapeake it becomes iiiori; of a grayish 

 green in color, the glauconite being less oxidized and the formation as a whole not 

 eiLsily distinguished, if, indeed, it can be separated from the Navesink formation 

 which underlies it. 



RASCOCAS FORMATIOS 



The Rancocas consists of thick l)edded green.sand strata highly glauconitic and 

 weathering to a compact, deep re«l deposit upon its thinned out and exposed mar- 

 gins. In New Jersey the strata an* highly fossiliferous, esj»ecially the Trrchratiila 

 Imrhiui z<jne, which is the most persistent fossilifenjus horizon in the static. 



The liiincocas formation luus been traced to the eiwtern counties of .Maryland, 

 where it occurs well exposed and highly foasiUferous on the upper Sa.>^safras river 



