1884.1 211 [Wadsworth. 



contour. The fact that this is a worn specimen and that the matrix 

 does not appear to be distinct from the filling of the supposed 

 chambers of the fossil would naturally excite suspicion, but could 

 not be considered conclusive unless demonstrated microscopically. 

 The differences of contour between the lower and upper expo- 

 sures, however, are fatal to the supposition that it is an Endoce- 

 ras, or any other known form of chambered cephalopod. Con- 

 siderable irregularity in the width of the chambers does occur in 

 some specimens of Endoceras, but hardly so strongly expressed 

 as in the folds on the left of this fragment. It would strike one 

 well acquainted with the Endoceratidse also that the chambers 

 have reversed curvatures, that is they are convex instead of con- 

 cave, an unheard-of modification among the Nautiloidea, 



" You have already pointed out the essential lithological charac- 

 teristics of the example under consideration, and it is probably 

 owing to this fact that I also notice on the left side a return con- 

 tour which looks like the beginning of a third fold. 



"Paleontologists are not apt to expect such close pseudomorphs 

 of fossils. This and other examples like one also now in Professor 

 Hall's possession, and a much closer copy of a Cyrtoceras or Nau- 

 tilus than this of an Endoceras, should be published as Carefully as 

 if they had been real fossils. They could be made quite useful in 

 the shape of cautionary signals, and would prevent many mistakes. 

 The facts noted by you, I have also seen and verified to the extent 

 my knowledge permitted, and the accidental separation of the red 

 nib of the apparent sheath, and the aspect of the exposed surface 

 of the calcite, settle the question against any attempt to consider 

 it as the terminal point of a true sheath." 



The specimen was received from Mr. James T. Hodge, some 

 twenty-five or thirty years ago by Professor Hall, but he is 

 in doubt whether it is from Eagle River, or Copper Harbor. 

 Prof. J. D. Whitney, however, remembers a similar form, found 

 at Copper Harbor about 1850, hence, it is probable that this is 

 from the same locality. Professor Hall states that it remained in 

 his possession unnoticed so long because he not only hoped to 

 visit the region, but also because he hoped that other specimens 

 would be found. 



In order that no one may think that the present writer is unduly 

 anxious to place this form in the mineral kingdom, it may be pointed 



