ELISHA MITCHELL SCIENTIFIC SOCIETY. 63 



(3) It ma}^ be an org-an of some animal. The form 

 represented in iig-ure 17 is a "cast of what Nathorst 

 considers to be the radial canals of a species of a cras- 

 pedot Medusa, belong-ing- to the family ^Kq^uordae." ^ 



(4) They may prove to be of vegetable orig-in; an- 

 other variation of the many and striking forms assumed 

 by sea plants. 



From the peculiar nature of the knob and cavit}^ I 

 offer as a bare sug»-gestion that in their original growth 

 they were probably joined togther as in Fig. 18. 



These are mere sug'gestions to show that the palffio- 

 trochis is not vvholly unlike all org-anic forms, 

 thoug'h it can not yet be assig"ned a definite place among 

 org-auisms. 



The purpose of this examination has been to call at- 

 tention to the work done on the pala^otrochis, to in- 

 vestigate the methods by which the results were ob- 

 tained, and to see if the concUisions reached would 

 stand the test of an examination made in the lig-ht 

 of more recent discoveries and by more modern meth- 

 ods. 



I claim (1) that neither Kmmons, Hall, nor Marsh 

 made that careful and scientific investigation of these 

 forms necessar}' to just if 3^ the conclusions reached, and 

 that these conclusions should not be accepted. And I 

 claim (2) that the weig'ht of evidence in the present 

 state of knowledg-e indicates that the pala^otrochis is 

 of organic origin. The reasons briefl}' summed up are: 



(1) Its distribution in the rock. (p. 54) 



1. lOth Annual Report, U. S. Geological Survey, 1888-'89. Plate 

 op. p. 676. 



