NIAGARA AND LOWER HELDERBERG GROUPS. 131 



In reviewing the facts, and considering the known range and 

 extent of the Niagara and Lower Helderberg gronps, their 

 close approximation or actual contact over large areas, and 

 their wide separation in other places, we are compelled to the 

 conclusion that there are no two groups, of similar compo- 

 sition, in the entire palaeozoic series, which are so clearly dis- 

 tinct and which can be unmistakably traced over so wide an 

 area of country, both in their physical and lithological charac- 

 ter, as well as in their contained fossils. 



That there are designations among some of the formations 

 which are superfluous, we are willing to admit ; but the prop- 

 osition to drop from the system one of the most widely dis- 

 tributed formations of the country, whose geological position 

 and relations, and the fossil contents of which are so well 

 known, is scarcely the proper mode of improving "the nomen 

 clature of the American rocks." 



[Note. — The Map, in illustration of the above article, which was to have 

 accompanied it, is unavoidably deferred. It will appear in the following (28th) 

 State Museum Report.] 





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