30 



NOTES 0]Sr THE GEOLOGY 



are very refractory, and some of them have been employed as furnace-hearths. On 

 Decker's creek a small seam of coal, three or four inches thick, has been found in 

 this rock. 



Coals, 1^0 18 and 20, seem to represent the Tionesta group of Pennsylvania. As 

 exposed on Decker's creek, they are of no importance. ISTo. 18 gives the following : 

 coal 8 in. ; shale 4 in. ; coal 1| in, ; shale 2 in ; coal 1 in. ; shale 1 in. ; coal 4 in. A 

 very hard, refractory sandstone lies between the coals, and contains numerous indis- 

 tinct vegetable impressions. No. 20 is one foot thick, and of good quality. On 

 Decker's creek these may be seen near the bridge, below Hagidore's mill. On Booth's 

 creek only one of the seams was seen. Its thickness is 18 inches. At !N^uzum's mill 

 it is as irregular as the Briar Hill coal of Ohio. Along the railroad cutting, for some 

 distance, it shows itself about three feet thick, but as it approaches the station, the 

 underlying fire-clay increases in thickness, while the coal diminishes, until at length 

 the coal entirely disappears. At this locality the bed has been worked to a slight 

 extent, and has yielded a coal of excellent quality. The fireclay seems not to be in- 

 ferior to that of Dover, Ohio, which it resembles greatly. 



The Iron Ores of this group are of some importance. — In ISTo. 6, the ore is a rich 

 hematite, in nodules which frequently contain sharp vegetable impressions. This ore 

 was extensively used at the old furnace on Decker's creek, as well as at Clinton 

 Furnace. — In l^o. 21, there are two bands, quite persistent. The ore is quite im- 

 pure, but works well when mixed with better ore. At J^uzum's mill, a very extensive 

 deposit rests on this shale. The ore is very good, but is in immediate connection 

 with the fire-clay, upon which it sometimes encroaches. The nodules are frequently 

 encrusted with the clay, which may, perhaps, prove a hindrance to successful working. 

 These ores have been thoroughly discussed by Prof W. B. Rogers in his report on 

 property connected with the Pridevale Iron Works, on Cheat River. 



THEGREATCONGLOMEKATE. 



This formation varies considerably in character, some of the strata being very 

 coarse, with quartz pebbles, three-quarters of an inch thick, while others are fine- 

 grained, and resemble quartz, etc. It disappears on Cheat River, near Ice's Ferry, 

 on Decker's creek, near Hagidore's mill, and on the Monongahela, near l^uzum's mill. 

 In the gaps made by these streams the channels are obstructed by huge masses of 

 the rock, some of them as large as an ordinary log house, and weighing not less than 

 one thousand tons. At no point is it well enough disclosed to afford satisfactory 

 measurement or a knowledge of the succession of strata, so that our information is 

 derived chiefly from borings. 



