60 JOURNAIv OF THE 



is not similar to any concretion or class of concretions 

 heretofore described and that it has no anology to 

 cone-in-cone or stylolites. Let us now examine the evi- 

 dence by which Professor Marsh came to the conclu- 

 sion that it is not a coral and see if he was justified in 

 that conclusion. 



His conclusion, g-iven on pag-e 52 of this paper, is 

 not drawn from the form or external marking's, but 

 when he examined the interior with a microscope and 

 found no organic structure he deemed the evidence suf- 

 ficient and concluded that in the future this name 

 should be dropped from the g-enera of fossils. If he 

 had found org-anic structure of course the proof would 

 have been direct and positive, but the absence of or- 

 ganic structure is by no means a proof that it is of in- 

 org'anic origin, for Nicholson and Lydekker say, in 

 speaking of replacement by silica, the following*: "In 

 a larg-e number of cases of silicification, the minute 

 structure of the fossil which has been subjected to this 

 change is found to have been more or less injuriously 

 affected, and may be altogether destroyed even thoug-h 

 the form of the fossil be perfectl}^ preserved. This is 

 the rule where the silicification has been secondary, 

 and has taken place at some period long posterior to 

 the original entombment of the fossil in the enveloping 

 rock."^ 



Therefore it appears that Marsh's determination can 

 not be relied upon. 



(4) Was Professor Kmmons justified in his state- 

 ment that it is a coral? It is true the g-eneral form, the 

 radiate striae, or grooves, and what he took to be 



1. Manual of Pala:ontolog-y — Nicholson and Lydkekker. Vol. 1. 

 p. 7. 



