Series 1 includes files of Coxe Brothers & Company, Inc., the Lehigh Valley Railroad, William J. Wilgus and other engineers, relative to the valuation of collieries and anthracite coal lands either owned by or under lease to Coxe Brothers & Company, Inc. Correspondence and notes relative to appraisals and valuations for each colliery are included. There are also numerous blueprints of colliery structures, miscellaneous surface features, mine workings and other colliery-related items depicted on these blueprints. Box 5 contains different types of materials, including cross sections, improvement charts and lease abstract sheets pertaining to various Coxe Brothers' collieries, which is why they have been arranged in a separate container. All the materials in Series 1 are arranged alphabetically by colliery or subject.

This series contains twenty bound volumes relative to the Coxe Brothers valuation conducted by Wilgus. Eight of the notebooks cover Mechanical and Structural Features, Buildings, and Miscellaneous features at Coxe Brothers' collieries, with one containing data relative to the property of the New York & Middle Coal Field Railroad and Coal Company. Numerous photographs of colliery structures, colliery equipment and dwellings taken during the valuation are included in the notebooks. They also contain lists of colliery buildings and miner's dwellings, electrical equipment, mechanical equipment, flumes, railroad trestles, and many other types of colliery items. Valuations for all the different types of equipment and supplies are included, as well as general property descriptions, colliery and property maps, and blueprints of the layout of the various collieries. Sketches of various colliery structures, miner's dwellings, railroad tracks, flumes, and machines are also contained in the notebooks. The numbering system on these volumes seemingly indicates that there may be volumes missing, however, the set of volumes appears to be complete. These volumes would be very useful to anyone wishing to understand how an early 20th century anthracite coal production facility was organized and operated.

Twelve smaller notebooks are also included in this series. They contain field notes relative to either coal or mechanical and electric equipment. There are five coal notebooks, which contain data concerning the location, thickness and pitch of coal veins, and the location and length of underground tunnels, called gangways, which were dug to reach coal veins, as well as transport men and coal through the mines. The mechanical and electrical field books contain sketches and data pertaining to equipment at various Coxe Brothers' collieries, such as boilers, engines, and steam pipes. The volumes are organized by their type, either notebook or field book, then by subject.