MOUNT LAUREL^NAVESINK. 131 



ANALYTICAL DISCUSSION OF THE MOUNT LAUREL-NAVESINK 

 FAUNA. 



The following summary presents the data recorded in the above 

 table in a condensed form, showing the number of species com- 

 mon to the Mount L/aurel-Navesink and to each of the other for- 

 mations in the series. Fifty-four of the total 112 species in the 

 fauna, or 48 per cent., have not been recognized in any other 

 horizon : 



Cliffwood,. 4 



Merchantville, 28 



Woodbury, 14 



Marshalltown, 20 



Wenonah, 26 



MT. LAUREL-NAVESINK, 112 



Red Bank, : 23 



Tinton, 22 



Ripley Group, etc., 48 



A careful analysis of the Mount Laurel-Navesink fauna shows 

 several peculiar characteristics in which it differs from any of the 

 other faunas of the series. In the first place the number of recog- 

 nized species is larger than in any of the other faunas, a fact 

 which might be due to the larger number of localities from which 

 collections have been examined. However, from many of the 

 localities recorded, it was quite impossible to make complete col- 

 lections, and only a few of the common species, such as could be 

 gathered in a few minutes' search, were secured, and while the 

 larger number of localities may account in part for the larger 

 fauna, it cannot wholly do so, and it is certainly true that this 

 horizon actually does contain a larger fauna than any of the 

 others. 



In the second place this fauna contains a much larger propor- 

 tion (48%) of species which are restricted to it than does any 

 other in the series, as may be seen in the following table 

 showing the percentages of restricted species in each fauna. 



