Maryland Geological Survey 173 



ence of carbonaceous matter does not tend to give that color but rather 

 the blue-gray. Perhaps the color is in some way the result of the char- 

 acteristic on which these beds have been differentiated, the mixture of an 

 abundance of fine-grained sand with a moderate amount of clay, which 

 results from the wide range in the size of the material forming the bed. 

 That is to say, these beds being predominantly fine-grained should con- 

 sist mainly of extra-fine sands with much clay. But as a matter of fact, 

 while most of them are very high in extra-fine sands and contain much 

 clay, they contain, in many cases, even more very fine sands, and usually 

 also a considerable proportion of some of the coarser sizes. The most 

 marked exception to this general wide range in sizes is sample 5, which. 

 as just stated, is really a glauconitic open-water deposit. Sample 6. which 

 is closely associated with sample 5, shows much less divergence from such 

 composition; while all the others satisfy reasonably well the description 

 just given. Sample 9 diverges from the normal estuarine type again 

 in the other direction, that is, towards the delta type; but its affinities 

 with this type were already pointed out in the summary and discussion 

 of it. To a somewhat less extent the same is true of sample 11, as 

 was also explained in the summary and discussion there. These diver- 

 gences all serve merely to bring out the intermediate character of the 

 estuarine type. 



In conclusion, if the distribution of the three types of sediments as 

 defined in the different formations is considered it is found that the 

 samples studied from the Magothy are distinctly of the delta type. In 

 the Matawan and in the Monmouth both the estuarine and the open-water 

 glauconitic types are found. This is not surprising. Even without the 

 evidence afforded by sample 10 for the Monmouth we know and might 

 expect that in both periods there was transgression, and this transgression 

 might well be estuarine in its basal portion. Thanks to the good section 

 afforded by the Chesapeake and Delaware Canal, the relation of samples 

 4 to 8 is clear, and it is in conformity with this relation that the higher 

 portion represented by samples 7 and 8 should be of a deeper-water type 

 than the lower portion (samples 3 to 6). The stratigraphic relation of 

 12 



