22 



SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 



began field-work in an investigation of the Cretaceous rocks of 

 western Xew Jersey, where the prime object was to secure suitable 

 exhibits of such economically important rocks of organic origin as 

 glauconite or green sand, and calcareous marl. The green sand 

 area in the vicinity of Vincentown, New Jersey, afforded the best 

 results in fossil and rock specimens for both study and exhibition. 

 The very incoherent green sand could not be obtained in masses of 

 a size suitable for exhibition, but by the use of shellac a large piece 

 was hardened sufficiently to be shipped to ^^'ashington without 



Fig. 22.— Marl pit at Vincentown, N. J. Photograph by Bassler. 



breakage. In the marl pits unusually well-preserved fossils were 

 found scattered through an unconsolidated sand formation. Here 

 specimens abound literally by the millions, and large numbers were 

 collected by passing quantities of the sand through a fine-meshed 

 sieve, the residue in this process usually consisting of nothing but 

 well-preserved fossils. The amount of sand sifted is shown by the 

 excavation seen in figure 22. The undulating line marks the 

 irregular contact or unconformity between the Cretaceous marl 

 formation and the overlying strata of more recent age. At the point 

 B in this photograph the fossils occurred in especial abundance. 



