8 



Erwin H. Barbour, 



west, I believe that no one, till further facts are obtained and 

 until the material now brought together is worked out, can 

 make any positive statement as to what these extraordinary 

 fossils are. Accordingly, I shall treat of them cautiously and 

 tentatively, awaiting the discovery of additional facts, and 

 shall withhold for the present the classification which I had 

 hoped to offer. 



That they could ever have been formed by burrowing ani- 

 mals, by geysers or springs, or by any mechanical means 



Fig. 5. — The right bank of a small draw near Eagle Crag, showing the more impor- 

 tant ones of the many corkscrews in sight when sketched. 



whatever, is entirely untenable. Neither are they accidents, 

 mere freaks, or concretions. Their organic origin cannot be 

 questioned, — as it seems to others who have seen them as 

 well as to myself. 



If they are sponges, — as I am inclined to believe, — then 

 Miocene sponges are all the more remarkable, judging by 

 our present diminutive fresh-water varieties. Moreover, the 

 existence of spicules is not demonstrated, though certain not 

 infrequent rod-like bodies may prove such. Add to this the 



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