294. GEOLOGY OF OHIO. 
mines already reported. The best coal is in the lower bench, which is 
here 23 feet thick, and consequently a good deal of it is brought out in 
merchantable shape. The uppermost part of the seam is the hardest 
and strongest coal, and immediately over the main parting a softer por- 
tion occurs. In addition to the main parting, which is a two-inch slate, 
there is one regular band about two feet below the roof of the seam, 
and there are the usual “binders.” 
The structure is shown in the accompanying plate: 
PFLGURE WRU 
STRUCTURE OF CAMBRIDGE COAL SEAM 
AT: NICHOLSON S MINE (N°SWAMP” 
Root Shaulers. = ee ie at ————— 
Ce a SAE Nw 
The composition is shown in the following analysis : 
Coallotathe Nich olsoneminer cess cere eee eeeeenonee an Lord. 
IMPOISEURE Weietatiescadetonae a letec sac soweeee dace deans ootnivenee Nee emer emenneenentccn testes 3.84 
Volatile matterya se A ee Se, Se eee eae 37.90 
IDib-de10 Wess hd ov) DENS PR DD RA RaAemUrr CER Dro ne or ocnic aon UnEBEcabcosduoouocd dab hococons 53.83 
AT | 0 WER PRPS ESS RRR COREA Pat OR In ORR TCR R CEE CRE ab» BoCated GoSeGBGod bdouoU GetidoD 4.43 
100.00 
Sulpluane Ma ise. cesere ov ecceeessan ces classecandecseece cae uecnanaenencaceceeees 1.36 
It is apparent that such figures mark one of the finest coals of the 
State. The physical qualities of strength and hardness alone are lack- 
ing to make this the peer of any Ohio coal. | | 
The Akron and Cambridge mine at Byesville is another of these 
regular and uninterrupted bodies of coal, without horsebacks or clay 
veins. Its composition is shown in the appended table: 
