Maryland Geological Suhvey 319 



Jersey rested on the assumption that the New Jersey Coastal Plain was 

 subjected during Upper Cretaceous times to a series of slight oscillations, 

 and that concomitant with these oscillations of the sea bottom there was a 

 shifting of the faunas back and forth so that a given fauna remained con- 

 stantly under a given depth of water and reappeared at intervals through- 

 out the epoch. Whether or not this alternation of faunas which Weller 

 postulates is due to oscillations of the sea bottom or to other causes, 

 such as a slight shifting of the in-shore currents, or a difference in the 

 amount and character of the sediments brought down by stream erosion, 

 is open to question. 



It is highly improbable, however, that his " Cucullaea " fauna which he 

 has found characteristic of and recurrent in the more glauconitic beds of 

 the Merchantville, Marshalltown, Navesink, and Tinton lived at a depth 

 of more than fifty fathoms. All of the Upper Cretaceous faunas of the 

 Middle Atlantic Coast are essentially shallow-water faunas and it is 

 probable that the fauna! differences are due rather to varying proximity 

 to stream mouths and sediment-bearing currents than to the relatively 

 slight differences in the number of fathoms. 



Weller's major groupings seem, in the light of the work done by 

 Stephenson in the Southern Atlantic states, less happy. Weller recog- 

 nized but two major divisions, the Ripleyan, covering all from the base 

 of the Magothv to the top of the Monmouth, and the Jerseyan, including 

 the Eancocas (Hornerstown and Vincentown) and Manasquan. The 

 Ripleyan as used by the New Jersey Survey has a wider faunal range 

 than the Eipley formation of the eastern Gulf region which, as defined 

 for that region, is the equivalent only of the Monmouth. The formational 

 names Matawan and Monmouth have been repudiated even as group 

 names by the New Jersey Survey, although first used for these divisions 

 in that state. 



Weller has maintained that " from the faunal point of view the recog- 

 nition of a Matawan division and a Monmouth division in New Jersey is 

 strictly arbitrary and unnatural. Some species, to be sure, are restricted 

 to the lower formations of the series and others to the upper, but there is 



