The Oriskany is a somewhat regular sand body in an area comprising parts of fourteen counties in eastern Ohio. The western limit of this consistent deposit can be plotted as a very irregular line between Trumbull and Meigs counties. Although relatively large lenses of sandstone have been encountered at this horizon as far west as Knox County in the central part of the state, only two small fields have been discovered in western outliers.

The Cambridge field, discovered in 1922, was developed along the western pinch-out of the Oriskany in a typical stratigraphic trap extending from southwestern Guernsey County into south-central Tuscarawas County. The sand was absent west of the field, oil has accumulated immediately below the gas and a definite water horizon was encountered on the normal southeast dip below the oil at a depth of 2,600 feet below sea level. Although hard and sharp, the sand was exceptionally open in texture. Virgin rock pressure was 1,150 pounds. Gas wells were large in volume but relatively short lived. At its peak in 1926 the field produced 190,000 MCF per day.

During 1935 a small gas field with a virgin pressure in excess of 1,600 pounds was discovered on a closed structure in Madison and Wayne townships, Columbiana County, at an average depth of 3250 feet below sea level. The few wells drilled were soon ruined by water and the field was of no commercial importance. During 1946 a gas field was developed on a similar structure and at approximately the same depth a few miles east in Madison Township. High pressures and large initial volumes encouraged development but water encroachment ruined these wells within a year. These two small gas fields are the only producing areas developed in Ohio where accumulation in the Oriskany sand was definitely controlled by anticlinal structure.

In 1944 a gas field was discovered along the western limit of the Oriskany in eastern Knox Township, Columbiana County, at an average depth of 2,400 feet below sea level. Initial rock pressures were in excess of 1,300 pounds. Although no oil was discovered downdip, high permeability of the sand and large initial volumes of the wells indicate that their history will be comparable with that of the Cambridge field.

A gas well with an open flow capacity of 2,500 MCF was recently completed at a depth of approximately 2,100 feet below sea level near the Pennsylvania line in Vernon Township, Trumbull County. It is one location west of two small oil wells which are located immediately up the normal dip from

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four dry holes completed in water bearing Oriskany sand. These tests are located within a distance of one mile east and west and indicate the possibility of a stratigraphic trap along the western limit of the sand in that area.

The position of the Oriskany sand in the series of Devonian and Silurian limestones and dolomites called the "Big Lime" and its possible correlation with the Austinburg sand in Ashtabula County are discussed.

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