130 E. C. Case — Amphihicm Fauna at Linton^ Ohio. 



Generalized section for Tnscawaras County. 



In North In South 

 Ft. Ft. 



Coal (Upper Freeport) 3 4 



Interval 70 35 



Coal, 6a (Lower Freeport) thin 2 



Conglomerate, sandstone, and shale (Free- 

 port) 50 52 



Coal, 6 (Middle Kittanning) 4 4 



Orton's section of northwest Guernsej^ Count3^ 



Upper Freeport Coal bed, Cambridge thin 



Clay, Upper Freeport limestone 10 



Interval __ . _. 50 



Lower Freeport Coal bed thin 



Middle Kittanning 3 



Stev^enson remarKs in the article quoted above, page 71, that 

 the " Lower Freeport shows abrupt and extreme variations in 

 thickness (in eastern Ohio) as well as in qualitj^ and occasion- 

 ally carries on top a thick deposit of impure cannel." 



A study of these sections taken in all directions from Linton 

 shows that the Freeport Coal either becomes thinner, loses its 

 fire clay (the leached ground soil of the marsh in which it was 

 formed) or the accompanying layers become disturbed by inter- 

 calated beds. While it is admitted that the Lower Freeport 

 Coal is variable in thickness and quantity, in almost every 

 place where it is known, the peculiarity of the thickening at 

 Linton, the presence of underlying cannel coal, and the undis- 

 turbed deposition of the accompanying shales and sandstones 

 is at least strong confirmatory evidence of the presence of an 

 open pool in the center of a great swamp. 



Of the Lower Freeport sandstone, I. C. White says,^ " It is 

 one of the most persistent sandstone horizons in the Allegheny 

 series. . . . The rock is usually quite hard, micaceous, and 

 often pebbly, but does not split evenly." In the western part 

 it is very uniform in character, running from 75 to 100 feet 

 thick, but toward the east (station 1 on the map), it is broken 

 by shale and a thin bed of coal (Upper Kittanning). 



In the time before the deposition of the Lower Freeport 

 Coal, the Linton area was evidently for a considerable time a 

 region of deposit from moving water bearing the debris from a 

 region undergoing rapid denudation, as is shown by the pres- 

 ence of undecomposed mica and the pebbles included in the 

 matrix. This was one of the longer ^Deriods of depression in 

 the region and the depression was extended over a wide area. 



* White, I. C, Geol. Surv. West Va., vol. xi, page 478, 1913. 



