11.2 PROCEEDINGS OF THE AMHERST MEETING 



Mr. Higgins: To name beds below the arbitrary zero bed would require but 

 the prefix of a niiuus sign. Slight changes, from 49g to 49c, for example, are 

 of no practical import to the engineer, for in estimating reserves he requires 

 only a convenient scale. 



Dr. Ashley, in reply, pointed out that his proposed nomenclature was pri- 

 marily for adoption for a type section against which future work may be set. 



REVISION OF TEE PALEOZOIC SYSTEMS. PART II: THE ORhOYlCI AN 



SYSTEM 



BY E. O. ULRICH 



(Abstract) 



The paper gives a definition of the Ordovician system as restricted in the 

 first part, followed by more or less detailed notes on the formations and their 

 correlations. 



Head in abstract from manuscript. 



Discussed by J. J. Galloway, G. H. -Chadwick, A. F. Foerste, K. S. 

 Bassler, and Arthur Keith, with reply by the author. 



Discussion 



Dr. Galloway : I wish to call attention to the unconformity above the Moc- 

 casin red limestone, the color of which is due to weathering during the uncon- 

 formity. 



Dr. Foerste : The paper by Dr. Ulrich is an excellent illustration of the 

 limited geographical area occupied by some formations and of the frequency 

 with which strata of similar lithological appearance in areas not far apai;t 

 may belong to more or less distinct parts of epicontinental basins, may contain 

 distinct faunas, and may belong to distinct horizons. It demonstrates the 

 danger of identifying formations in new areas on the basis of relatively few 

 fossils before their faunas are more fully known. Within relatively small 

 areas it frequently is possible to demonstrate the presence of quite distinct 

 basins of depositions. The Niagaran of Adams and Highland counties, in 

 southern Ohio, for instance, is quite different from that in the more northern 

 countries, Montgomery, Miami, and Darke. The latter, again, differ from the 

 Niagaran of Indiana. And yet those very different areas of deposition lie 

 within relatively short distances from each other. 



The section adjourned at 5.20 o'clock p: m. 



Session of Wednesday Evening 

 presidential address and smoker 



At 8 o'clock Wednesday evening- the address of the retiring President 



was delivered in College Hall. It is entitled 



