170 GEOLOGY OF OHIO. 
given territory, unless very careful and generally quite expensive in- 
vestigation has been carried on. The method referred to is unsatis- 
factory at best. A farm is often drilled over two or three times, by as 
many different lease-holders, before the coal basins are found. The 
work of testing is still going forward, but with constantly diminishing 
force, inasmuch as the chances of any considerable deposits being struck 
are lessened year by year. Small basins are, however, still being dis- 
covered and developed, but a few years at most will terminate the 
production of coal in Trumbull county on the large scale. 
The characteristics of this field have been so fully set forth in 
previous reports (see especially Newberry’s report on Mahoning county, 
vol. III; and Read’s report on Trumbull county, in report of 1870) 
that it is not necessary to go into full details here. It is, however, to 
be remarked that quite different grades of coal come into market under 
the name of Mahoning Valley Block coal. The name does not in all 
cases stand for fuel of the highest excellence, but it is sometimes made 
to cover common, or even quite inferior quality. The bulk of the coal 
fully deserves its excellent name. 
But few analyses of the Block coal have been made for the present 
volume, partly because the character of the coal is so well established, 
and partly because the field is losing its importance as a source of 
coal. 
The best portions of the seam yield excellent results, as shown in 
the following analyses, made by Wormley and quoted by Newberry, 
vol. III, p. 813: 
INOM lee eBriersral lfeoalMecccsssnccses Dodoo on dieae ase eased detoesecdscieeeeeenees Wormley. 
No.2... WVeatel’simin einticseccscsccuss oo icesee ena ceon cece eer eec oaeee senate oh 
No. 1 No. 2 
IMFOISEUT OC viesbaiieejecisoen acon d hamsters meee eee Tee a aes One ae ac neo eee 3.60 247 
Volatile combustible matter..........cscescsscccceccsees Jey Soe aan onan 32.58 31.83 
Dab: 70 WK Gt: Wl 010) 0 RRR RA Br ests eR Ben a. ASCE Son R ANG ooSC ANDO COCDCCREODIGHOSOS G8CCae 62.66 64.25 
UNI) 0 SEER HEP PES OPER RAE A ee 8 GRE a APES A VEER Ol ar sac 1.16 1.45 
100 100 
SU]PHUP iccvcciocecceessescenseccueteciieesoosesscovanescacsorecssaeronesesoneeene 0.85 0.56 
