Ashburner.] OOO [March IS, 



ment of the coal fields has been misdirected, and consequently retarded. 

 Investments have too often met with disappointment, followed by failures. 



A geologist cannot manufacture good coal beds or purify poor ones ; and 

 he steps beyond his professional bounds as a practical geologist when he 

 attempts aught else than the discovery of facts and their true economical 

 interpretation. 



If there are any advantages to property holders to be derived from too 

 favorable and rose-colored reports, they are certainly only immediate and 

 are insignificant in comparison with the more permanent ones resulting 

 from true, unbiassed and less favorable reports. 



I have prefaced my paper with these remarks, because the results of my 

 examinations in the counties mentioned have two direct and important but 

 quite independent bearings ; one is purely commercial in its aspects, as it 

 interests and affects the land owner and coal operator ; the other belongs to 

 the province of pure geology concerning only the geological investigator 

 and student. 



It is my present purpose to merely describe a new interpretation which 

 I have made of the stratification in the vicinity of St. Mary's, Elk County, 

 and to indicate its bearing upon the systematic geology of other portions of 

 the district. 



Statement. — The detail geology of McKean has already been published 

 in report R of the Geological Survey ; that of Elk will be found in connec- 

 tion with the geology of Cameron and Forest in the forthcoming report RR. 



The local geologists of Elk County generally consider the coal measures 

 in the vicinity of St. Mary's to be low in the series ; whereas I make them 

 to include the representatives of the Lower Freeport, Kittaning, Clarion 

 and Mercer (or Alton) coal groups. 



I fully realize the fact that I am making a statement which is directly 

 opposed to the general views held in regard to the nomenclature of the 

 St. Mary's coal beds. But the most important and difficult problem which 

 I have had to deal with, has been the identification of the coal rocks ; and 

 the conclusions which are now advanced have only been reached after 

 a careful detail study of the coal basins of McKean, Cameron, Elk and 

 Forest counties. A great many observations have been made in adjoining 

 counties in order to confirm the work, and connect it with that done by 

 other survey assistants in adjoining fields. 



The fact that a rock section contains the representatives of certain well 

 known and established groups, does not necessarily imply that each group 

 has a well defined representation of the individual beds which characterize 

 it at the place of its best development. The special features which have de- 

 termined the naming of the sub-groups of the coal measures, at their typical 

 locality, may be wanting at many places where the occurrence of the group 

 itself can alone be determined by a comparative study of the entire forma- 

 tion. 



From the fact of the St. Mary's section containing the rocks of four of 

 the principal groups of the Lower Productive coal measures in the State, 



