PREFACE. 



The invertebrate Cretaceous fossils of New Jersey were among 

 the first fossils of any kind in America to attract the attention of 

 students. As early as 1834 Morton's "Synopsis of the Organic 

 Remains of the Cretaceous Group of the United States" was 

 published in its final form, a large portion of the material he 

 studied having been collected in New Jersey. Even earlier than 

 this the same author had published several preliminary papers. 

 During the period between 1850 and 1876 these New Jersey 

 fossils were diligently studied and many new species described 

 by both Conrad and Gabb, two of the eminent American paleon- 

 tologists of that period, and a few forms were described by Lea. 

 The collections made and studied by these earlier investigators 

 were for the most part preserved in the museum of the Philadel- 

 phia Academy of Science, where they stijl remain. Unfor- 

 tunately, in those earlier days, the importance of preserving 

 exactly the localities and geologic horizons of fossils was not 

 appreciated as it is today, and most of the specimens in these 

 early collections are recorded simply from the Cretaceous of 

 New. Jersey. 



After the organization of the Geological Survey of New Jer- 

 sey under the direction of the late Dr. George H. Cook, more or 

 less extensive collections of fossils from the Cretaceous beds of 

 the State were accumulated, but the data with these collections 

 was in many cases also unsatisfactory, largely because of the 

 lack of differentiation at that time of the strata of the "clay marl" 

 series. Under the direction of Dr. Cook a study of the New 

 Jersey Cretaceous fossils was undertaken by Prof. R. P. Whit- 

 field, who published a monograph on the Cretaceous and Eocene 

 Mollusca of the State. This work app.eared in two volumes, the 

 first in 1886, and the second in 1892, published jointly by the 



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