170 Association of American Geologists. 



elusive as to the opposite opinion. The facts are, that masses exist com- 

 posed of whole shells, as at Easton, on the eastern shore of Maryland. 

 That in some localities fragments of older fossils are found with them, 

 and which must have been thrown amongst the oysters by the waves of 

 the estuary from their position below. And again that deposits of the 

 shells exist in situations too remote from present oyster beds to have been 

 removed by human agency, such as those in Cumberland county, in New 

 Jersey ; therefore it would appear that both causes have operated to pro- 

 duce them, and that no single generalization can comply with the requi- 

 sition of the facts which they present, leading as they do to a twofold, one 

 from opposite conclusions, one referable to human, the other, to natural 

 causes, and that severally they must be examined in order to ascertain to 

 which of the two causes any given mass is to be referred.* 



Larpner Vanuxem. 



Prof. Booth stated that his observations upon these deposits 

 had led him to the same conclusion as that which had been arri- 

 ved at by Mr. Vanuxem, viz, " that they are sometimes referable 

 to human agency, and at others to natural causes." In answer 

 to an inquiry, Prof. B. observed that these shells reduced to pow- 

 der had been used with great success in the State of Delaware, 

 as a manure. Prof Hitchcock stated that the fertilizing powers 

 of these deposits of shells had also been tested by experiments 

 on Cape Cod. Facts were stated by the chairman and Prof 

 Mather in regard to beds of oyster shells similar to those descri- 

 bed by Mr. Vanuxem^ on the Island of Nantucket, and on Long 

 Island. 



Prof Bailey commenced his accoimt of "Fossil Infusoria," by 

 an exhibition and description of the microscope employed by him 

 in his researches. 



Messrs. Charles B. Trego and B. Silliman, Jun. were ap- 

 pointed assistant secretaries. The Association then adjourned 

 until 9 o'clock, Thursday morning. 



Third day of meeting, Thursday, April 8, 1841. — The Asso- 

 ciation met at 9 o'clock, A. M. Prof. Silliman in the chair. 

 The minutes of yesterday were read and adopted. 



* Since the meeting of the Association, I have found on conversing with Dr. Du- 

 catel that the impressions which I had of his views were founded upon his first re- 

 port, that of 1834, for in his subsequent ones, he makes known their twofold origin. 

 We should withdraw this paper did we not believe that it would be of service ; 

 for it not only settles the point in question, which was its object, but it affords a 

 useful lesson as to caution in an expression of the opinions of others. 



