12 CRETACEOUS PALEONTOLOGY. 



stratigraphy of the "marl" series, at least in Monmouth County, 

 was so exact that more recent investigations have not made it 

 necessary to change his subordinate divisions of this series in any 

 essential respect, although he did fall into errors in the interpre- 

 tation of some of the beds in their southwestern extension in 

 Gloucester and Salem counties: Cook's subdivision of the "clay- 

 marl" series into the "clayey green sand" below and the "lami- 

 nated sands" above, is of little or no utility at the present time, 

 but his divisions of the "plastic clay" series, so far as it occurs 

 in Middlesex and Monmouth counties cannot be much improved 

 upon even to-day. A tabular view of Cook's divisions is shown in 

 table I. 



The more recent investigations of the stratigraphy of the Cre- 

 taceous formations of New Jersey have been conducted by Dr. 

 W. B. Clark, Mr. G. N. Knapp and Dr. H. B. Kummel, all work- 

 ing more or less independently. 



Clark began his study of the region in 1891, the results of his 

 work being published in the Annual Reports of the "Survey for 

 1892, 1893 an d 1897. The subdivisions which he recognized 

 were not essentially different (from those of Cook, but instead of 

 the lithologic names used by Cook, geographic terms were used 

 for the designation of the formations, and in his later publications 

 he did not repeat the error which Cook made regarding the south- 

 west extension of the Red Sand and Lower Marl. 



Table II shows these subdivisions in a tabular form. 



All the geographic formation names used by Clark were 

 original with him except Raritan. This name had first been 

 applied to the lowermost division of the New Jersey Cretaceous 

 by Conrad 1 in 1869, but without any definite statement as to the 

 upper limits of the formation. Since that time the name has 

 been frequently used by various authors, but has usually been 

 applied to the clay beds so extensively worked near the Raritan 

 River. Clark was, perhaps, the first to assign a definite upper 

 limit to the series in applying the name to the whole succession 

 of beds beneath the "clay-marl" series of Cook, or the Matawan 

 formation as it was called by Clark himself, except the lignitic 



'Am. Jour. Sci., 2d Ser., vol. 47, p. 360. 



