GEOLOGY & NATURAL RESOURCES. Cleveland sits at the junction of 2 major land types. From the Portage Escarpment southeast and east of the city, the glaciated Allegheny Plateau rises in gradually higher ridges to the Appalachian Crest. To the west the Central Lowlands roll across the prairies of Illinois to the trans-Mississippi plains. Abutting the Portage Escarpment and overlapping the Central Lowlands plains, a series of ancient lake beds and beach ridges lie across the northern 2 to 6 mi. of the region, extending up the Cuyahoga Valley south nearly to Akron.

Within northeast Ohio, all mineral and stone sources are sedimentary. The closest nonsedimentary minerals are the upper surfaces of the igneous and metamorphic basement rock at depths approaching 6,000'. During the Ordovician period (ca. 600-500 million years ago), the area from Indiana through New York formed a vast but narrowing tropical sea off the coast of an ancient continent with deposits of lime from shells, then of silty clays. As the basin grew shallower, sands and corals and limey reefs were deposited. Continental uplift and volcanic island arcs formed shallow, brackish marine bays during the Silurian period (500-400 million years ago), forming the earliest sedimentary rocks, the Albion or Newburgh sandstones and silty limestones. Within those basins, rapid evaporation crystallized and deposited more lime, then thick layers of salts and thin lenses of gypsum and dolomite, the Middle Salina formation of interbedded siltstone, rock salt, dolomite, and gypsum; and the lower Niagara (reef) dolomite.

During the Devonian and Mississippian periods (400-300 million years ago), continued erosion from the continent began filling the shallow seas with red, gray, and black clays and limey silts. Finally, vast channels and deltas cut through and exposed mudflats, then filled with sand. Today these sediments are compressed into the bedded Mississippian deposits of siltstones and shales of the Cuyahoga Formation; the deltaic sandstones of the Berea Formation; and the silty shales of the Cuyahoga Formation; underlain by the lithographic Cleveland shales. East of Cleveland, where major tributaries cut down to meet the Cuyahoga, the exposed bases of these bedrock deposits are the Devonian shales of the Chagrin Formation, below which lie the Devonian series of Huron/Portage shales, Bass Island limestone, and Sylvania silica sandstone. Throughout the Pennsylvanian period (300-200 million years ago), fluctuating and deepening seas covered these deposits with alternating series of thin organic iron and limey silts; thin stringers of bituminous coal; and a thick series of coarse sands and gravels which today are compressed into the Sharon sandstone and conglomerate of the Pottsville series.

Ca. 180 million years ago, the slow collision of the African and North American continental plates crumpled these earlier deposits, tilting them up to the west, finally lifting the entire Appalachian Plateau above sea level. Erosion replaced sedimentation in northern Ohio until the last onset of continental glaciation during the Pleistocene epoch (ca. 1.3 million years ago), when glacial ice overrode northern Ohio. Alternating advances and retreats stripped the soils and ground down rock outcrops, filling the valleys and lowlands with deposits of sands and gravels, clays and boulders. Little evidence of the earliest glacial events, prior to 250,000 years ago, or the soils developed in interglacial times is preserved in northern Ohio. Most earlier glacial deposits were removed by the Wisconsinan ice advances (ca. 125,000 years ago), when thick deposits of sand and silt mixed with boulders, gravels, and pockets of clay, called "drift" or till, washed from the melting ice and were left on the eroded surface of the Central Lowland province. Ice from the Erie Lobe made 5 different readvances into northeastern Ohio, separated into 2 lobes by resistant outcrops of sedimentary rock. The lobes' margins, joining south of Canton, influenced the location of the early headwaters of the CUYAHOGA RIVER. The sequence of meltwater deposits comprises Mogodore till, Kent till, Lavery till, Hiram till, and Ashtabula till. Most of Cuyahoga County is covered by clays, sands, and gravels deposited as Hiram till more than 14,500 years ago.

The major event shaping the modern local drainage systems began when ice melted northward from the Akron region, leaving a boundary ridge of drift called the Wabash End Moraine ca. 16,000 years ago, which stood for 10,000 years as a drainage divide between the southward-flowing upper Cuyahoga River and Lake Erie. An ancient Lake Cuyahoga was ponded between the Wabash Moraine and retreating Hiram-age ice. During a subsequent readvance of the Hiram ice ca. 14,800 years ago, the Defiance Moraine was deposited just north of Peninsula. When this ice began retreating ca. 14,300 years ago, short-lived Lake Independence was formed. The major fill of the Cuyahoga Valley between Cleveland and Akron consists of deposits from these two lakes. Even after the northward retreat of the ice, minor climatic fluctuations resulted in changing water levels of the Great Lakes, resulting alternately in erosion or deposition in the river valleys.

From ca. 14,000-12,500 years ago, the Lake Erie basin was occupied by a gradually falling series of large lakes, all higher than modern Lake Erie. Erosion and deposition along their southern shores formed wave-cut terraces and beach ridges which generally parallel the modern lakeshore. Lakes Maumee I-III (14,500-14,100 years ago), were from 780' to 764' above sea level; Lakes Whittlesey I and II (ca. 13,800), between 740' and 730' above sea level; Lakes Arkona I-III (13,600-13,300 years ago), 711' to 690' above sea level; and Lakes Warren I-III (13,000-12,900 years ago), 686' to 670' above sea level. Between 12,900-12,600 years ago, the opening of the Niagara Falls outlet resulted in a rapidly lowering series of lakes (Wayne, Grasmere, and Lundy). By 12,200 years ago, the inflow of water from the upper Great Lakes had been diverted northeast, and the level of early Lake Erie fell 40 meters below its modern level of 571' above sea level. There was a slow rise to 565' between ca. 4,500-2,500 B.C., when erosion to the lowered lake levels downcut the old southern divide, enabling the upper Cuyahoga to join the flow northward into Lake Erie, the last major geological event to affect this area. Beyond shaping the topography, these geological events were responsible for the materials of economic significance to Cleveland's future development.

Throughout the Cleveland area, many of the glacial sediments and some rock layers carry water. The till plains and western outlier of the Glaciated Appalachian Plateau also contain major subsurface water resources. Throughout the region, soils developed differentially over the past 12,000 years, depending on the local "bedrock," slope, drainage, climate, and vegetation. On the uplands of the Allegheny Plateau, most soils are of glacial origin: poorly drained, rather unproductive heavy clay loam. Occasional patches of well-drained sandy soils exist as small terraces along some large streams. In areas near the glacial moraines, or on the lakeshore behind the beach ridges, soils range from sandy clay loam to coarse sandy gravels. Along the slopes of the escarpment rimming Cleveland, erosion prevents soil development and the surface consists of poorly consolidated shales and sandstones. Upon the Central Lowland till plains and within most of the Cuyahoga River Valley and its larger tributaries, soils are a mixture of sands, gravels, clays, and silts. Dry sandy soils characterize most of the rest of this zone. Prior to drainage, the clayey subsoils were unproductive. The occasional floodplain terraces along the Cuyahoga and lower Chagrin and Rocky rivers represent long, narrow soil zones of deep, well-drained, sandy silt loams—the major fertile soils in the region and prime agricultural land. Equally productive were the ancient beach ridges and the fragile and quickly depleted organically rich peat-filled lakes scattered from Collamer Bog, near the present COLLINWOOD RAILROAD YARDS, to Lake Abrahams, near the Intl. Airport.

Naturally, the mineral resources of the more recent sediments were exploited earliest. Sands, gravels, and clays occur so widely that there has never been commercial centralization. Iron-rich deposits of yellowish or bluish glacial clays occurred in pockets from 3-75' thick throughout the till plains, extracted in the early 19th century from open pits and locally fired for earthenware. The ancient beach ridges provided easily obtainable quartzite sands, used as early as 1802 for glassmaking. The old Cuyahoga River delta deposits and numerous kames (glacial stream deposits) yielded gravels used first as road metals, and subsequently for concrete.

Two rather ephemeral surface deposits were also significant in Cleveland's early history. Old postglacial "kettle" lakes filled with organic peat were exploited as truck gardens for the growing urban population of the early 20th century, then were cut, dried, and sold as fertilizer by the 1930s. More significant were deposits of bog iron, economically exploitable by open-pit mining, behind old Lake Arkona beach ridges from Cleveland east to Conneaut. Open-hearth furnaces at Painesville and Ashtabula processed some of the high-grade ore as early as 1833, but most of the production between 1837-59 was centered in the Cuyahoga flats. The Union demand for iron during the Civil War virtually exhausted these ore deposits; but while many Lake and Ashtabula county furnaces became archeological sites, those in Cleveland became a focus of the Great Lakes iron industry. With improvements in internal bulk transportation, by the 1860s more uniform sources of sand and gravel were obtained by crushing the Sharon sandstone and conglomerate east of Cleveland. Most production of finer ceramic-ware moved to Akron, where quality glacial clays were available, while the glass industry relocated adjacent to the Sylvania sandstone outcrops at Toledo.

As early as 1870, shallow open-pit extraction at Dover and Wickliffe recovered the Dekalb or Erie blue clays weathered from the Chagrin shale, used for paving brick and firebrick. Outcrops of the Chagrin shales were also mined in NEWBURGH, MILL CREEK, INDEPENDENCE, and COLLINWOOD for drain tile, paving brick, and common brick. Clays for face brick, fire brick, and hollow tile were extracted from Bedford shale and the lower (Euclid) shales, which still form most of the brick used in Cleveland. Berea sandstone, used for building walls and foundations as early as 1799 and still one of the region's major bulk exports, was from 1840 cut into grindstones and provided most of the curbing, building and bridge block, flagging, and trim for northeast Ohio, and is found in public and private buildings throughout the Midwest. Under the Berea sandstone lie the "Bluestone" Bedford shales which easily splits into even, thin layers and was quarried as early as 1834, providing Cleveland with flagging and cap and sill stone. "Bluestone" quarries began at Newburgh in 1847, with the large S. EUCLID quarry operating from before 1880 through the Great Depression.

One result of the 1859 Pennsylvania petroleum boom was a brief flurry of wildcat exploration in northeastern Ohio. While some wells yielded as much as 25 barrels per day, all were exhausted within several weeks. A well drilled by Newburgh Brick & Clay Co. in 1911 yielded 100 barrels per day the first week, then 35-40 barrels per day until it was exhausted in 3 months. The first significant by-product of the oil "boom" was the 1883 discovery of natural gas in ROCKPORT Twp. at 1,800', but far larger fields were tapped in 1886 at Newburgh at 2,660'. The largest gas fields were encountered between 1905-07 near Kamms and Berea. In 1912 a well set off a 1913-14 boom in LAKEWOOD and a 1914-15 boom in WEST PARK. By the 1930s, the last major natural gas pockets were tapped in the Denison-Harvard district.

"Rock Gas" was not the only natural methane available. Small decomposed organic deposits also yielded "drift gas" at depths between 125-450'. THOS. WHITE was the first to provide his home on Euclid Ave. with privately owned well gas for heat, light, and cooking from 1890-92. There are a number of similar individual wells still operating. The deep exploitation for natural gas had unforeseen results, encountering salt brine. By 1944 Union (Morton) Salt Co. opened a deep-shaft mine near Lake Shore Blvd. and E. 65th St., which went down into several levels of this Salina formation. Since 1957 large salt mines at WHISKEY ISLAND have been operated by AKZO NOBLE SALT.

David S. Brose

The Royal Ontario Museum and
Cleveland Museum of Natural History

Conceptual Cross-Section of Local Geology

Ancient Shorelines of Lake Erie

Major Rivers and Streams of Cuyahoga County

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