Weather more than favored us on the third attempt to make it to the top of Spruce Hill. It was easy-going up
towards the southern isthmus under a clear sky in the forty degree temperature. But as we walked along I
thought riding my nearby cousin’s horses would have made the trip more enjoyable.
Ten members and guests made the trip to what was probably once the largest stone-walled hilltop fort
in the North America. Jack Burgess got us to the fort and William Conner conducted the tour inside. Others
were Jim Leslie whose GPS receiver did not work, Ken Zimmerman who worried why seeing only a few birds,
Mike Murray and grandson John Murray snooped the site with a metal detector, Dr Hu McCulloch with his
maps, new member John Winkler, and guests Herb Wasserstrom and Jan Hatfield who discovered an early
blooming tiny white spring flower this Saturday afternoon on March 4, 2006.
The approach to the isthmus was wide and gently rose upward from the Paint Creek valley, and is said to
have been fenced on the east and west sides with tall, single-standing stones all the way to the isthmus.
From the record [E.O. RANDALL, THE MASTERPIECES OF THE OHIO MOUND BUILDERS, OHIO STATE
ARCHAEOLOGICAL AND HISTORICAL SOCIETY, 1908] we knew the isthmus width was about 700 feet with
the walls much thicker and taller here than the rest of the fort. Three equally spaced gateways were formed
by the inward curving and funneling of the walls into a narrow six-foot opening some forty feet inside the
fort. Now it lay before us, unrecognizable, only occasional scattered small clumps of Berea sandstone
poking out of the dirt and covered with leaves and undergrowth among a young saplings.
Further inside the fort, we walked northward along the western perimeter, looking for likely spots in the wall
where iron furnaces might have been. We noted a couple of possibilities due to oval depressions and a few
“squared” stones (see photo) likely human-shaped, but no definite surface artifacts of slag, glazed
stones or bits of iron ore.
We visited another gateway at the northern apex, similarly constructed as the isthmus but with a single entry.
Two more single gateways once existed in the eastern wall but, for some reason, had been walled-shut by the
original builders.
"Squared" Rock
The rest of the ancient stone wall around the perimeter rim of Spruce Hill was in the same state of ruin as the
isthmus wall. Even before early colonial area settlers removed most of the stones, trees growing in or near the
wall had tumbled the wall and scattered the stones.
The 140-acre enclosure tapered towards the center to form a natural pond with an earthen lip around it.
(A second pond is in the middle of the isthmus approach.) Mallery [ARLINGTON MALLERY, LOST AMERICA:
THE STORY OF IRON-AGE CIVILIZATION PRIOR TO COLUMBUS, WASHINGTON DC, 1951] thought it was a bog
iron ore pit, with a serpent effigy mound encircling it.
IRON FURNACES?
“The stone heaps at the great gateway give proof of having been subjected to intense heat, a feature also
discernible at certain other points in the wall.”. [E.O. RANDALL] . Two stone mounds located at points inside
the enclosure with extended viewpoints into the valley were found by E. O. Randall [RANDALL]. Both had been
burned throughout, suggesting to Randall their use of great fires perhaps for alarm signaling. But could these
be iron furnaces instead?
On a ledge below the ruined stone wall of Spruce Hill Mallery discovered in 1948 an ancient furnace, a hearth-pit
like those used in Europe before 1200 AD. To the west a short distance away, on a high promontory jutting out
from the same ledge was a circular stone-covered mound. Atop the mound, Mallery found a stone engraved with
Norse runes marking the entrance to a stone-vaulted burial chamber similar to chambers in the ancient
Scandinavian passage-graves. However, the runes proved to be the work of a local prankster.
Mallery also found what he believed to be nine more stone-lines graves lying on another promontory westward
beyond this vault. In another reference to Spruce Hill [MALLERY, P.201], he discusses the practice of calcination
[see Step 1 in the below box] of iron ore on a flat hearth as found in Turner Mound 3 in the Little Miami Valley, or in
small piles in the open field, as on Spruce Hill. So, the historical accounts of slag piles atop Spruce Hill were the
waste from the first step of iron extraction.
WHO WERE THE IRON FURNACE PEOPLE?
There is no evidence that any Ohio native Cultures used or smelted iron. A considerable number of copper
artifacts have been uncovered at the nearby Seip Mound complex, but no iron.
If not them, who? Well, someone who was in the area and had a need for iron; recognized bog iron
ore and knew how to smelt it. The furnaces found here at Spruce Hill and elsewhere in many locations in Ross
County were almost identical copies of those found in Europe during the Iron Age. The iron furnace people
were most likely these Europeans – Viking, Irish, Celtic people are possibilities.
When were they built? There seems to be no dates of these Ohio iron furnaces but most likely
they were built during the first millennium A.D.
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Primitive Iron Smelting
Step 1 – Calcination – The iron ore is piled on layers of wood bundles and fired until red
hot but below fusing temperature. This drives off volatile material and pulverizes the ore.
Step 2 – The calcinated ore is added to an iron furnace with more fuel and fired to just below
the melting point (2100°). Fusible material liquefies and with the iron moves towards the bottom
of the furnace. The clump is called a ‘bloom’. Mallery named this type of furnace Celtic. If the
bloom is drawn from the furnace into a clay receptacle, Mallery called it a Nordic furnace.
Step 3 – The fire is quenched with water and the still red-hot ‘bloom’ is removed and beaten
with stones and heavy hammers to force more slag from the iron. This can be repeated several
times, or re-fired and beaten.
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Inscribed Stone ?
A small flat stone was found on the western side and appeared to be inscribed with
irregular lines. Perhaps it has once been in the farmed area, ran over occasionally with a
tillage disc and then tossed out of the way?
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