148 GEOLOGICAL INVESTIGATION. 



importance to doubt, as to the correctness of this assign- 

 ment. 



When, about a year later, these numerous orthocera- 

 tites were found, a violent shock was thereby given to 

 this original determination of the horizon. The equi- 

 librium, however, was soon restored for awhile by dis- 

 covering also other fossils corresponding with some de- 

 scribed in the Canadian calciferous, notably, Ophileta 

 cojnpacta, Salter. This gasteropod is fortunately admi- 

 rably described and illustrated in Decade i., page 16, 

 Can. Geol. Survey. This evidence seemed so conclusive, 

 not only to myself but to several paleontologists of the 

 highest experience, to whom the specimens had been 

 submitted, that these orthoceratites were then accepted 

 as being indeed a new phase of our calciferous. 



If, as is undoubtedly to be admitted, there is far more 

 doubt as to the true geological horizon of these fossils 

 to-day, it is not at all because of any weakening of the 

 hitherto accepted evidence as to the presence of charac- 

 teristic calciferous fossils, but solely to the very remark- 

 able nature and extent of the cephalopods, brachiopods, 

 gasteropods and trilobites, which later explorations have 

 developed. These are so far beyond anything which has 

 been yet known in the so called calciferous of the United 

 States, if not that of Canada, that on this ground alone, 

 we are compelled to revise our earlier views. No real 

 discussion of the question is possible in the limits of this 

 article ; nor indeed would any such discussion be profit- 

 able at this stage of the investigation. Some of the fea- 

 tures of these fossils show close relations to- the Trenton 

 group ; in other respects they as remarkably and essen- 

 tially differ from that group, belonging in so far to ear- 

 lier types of fauna. This question is complicated by the 

 fact that the so-called " calciferous," both of the United 

 States and Canada, is itself seriously in question at the 

 present time. It is very likely that important modifica- 



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