CHAPTER IV. 



THE COAL MEASURES OR PENNSYLVANIA SERIES. THE DEVEL- 

 OPMENT OF ITS NOMENCLATURE AND CLASSIFICATION IN THE 

 APPALACHIAN PROVINCE. 



The classification of the rocks of middle Pennsylvania in 1836 furnished 

 the basis for the system of numbers which have played so conspicuous 

 a part in Pennsylvania geology ever since. The State geologist was 

 Henry D. Rogers, and his assistants were D. C. Booth and J. F. Frazer, 

 with R. E. Rogers as chemist. The classification was as follows : 



XII. Coal Measures. 



XI. Ked shale. 



X. White sandstone, ) e ., , 



w _ , , ) ot the second mountain. 



IX. Red sandstone, > 



VIII. Olive shales, etc. 



VII. Cherry sandstone. 



VI. Limestone. 



V. Red shale and Fossil ore. 



IV. Gray sandstone, } e ,, ~ 



TTT w ,-. -, , >of the first mountain. 



III. White sandstone, > 



II. Slate, ) of tbe Lebanon valley. 



I. Limestone, > 



The State geologist believed that this series of formations in the order 

 given could be recognized " under slight variations of color, size, and 

 mineral ingredients, across the Old Dominiou and into Teunessee and 

 Alabama." 1 



This constituted the "series of Appalachian formations," which Prof. 

 Rogers "for the first time systematically classified and described in the 

 years 1836, 1837, and 1838.* 



The geological survey of Pennsylvania was begun in 1836 and sev- 

 eral annual reports were published, but the final report was not pub- 

 lished till 1858. 3 



1 Second Geol. Survey of Pennsylvania, 1874-'75-'76. Historical sketch of geological explorations in 

 Pennsylvania and other States. By J. P. Lesley, 1876, pp. 54, 55. 



2 Second Annual Keport on the Geological Exploration of the State of Pennsylvania. By Henry D. 

 Rogers, State Geologist. Harrishurg, 1838, pp. 82, 83. 



3 The Geology of Pennsylvania, a Government survey, with a general view of the geology of the 

 United States; essays on the coal formation and its fossils and a description of the coal holds of North 

 America and Great Britain. By Henry Darwin Kogers, State Geologist. 4,to, 2 vols., Edinburgh, 

 London, and Philadelphia, 1858. 



83 



