What is an Atlas Block?
The block is the unit of area for which a separate checklist is generated. It is a 7.5 minute quadrangle. This universal map unit affords a convenient size area for birding coverage. Quadrangles can be obtained individually from the State of Ohio though the Ohio geological Survey. Far simpler, is to reference the Delorme Atlas & Gazetteer. This road atlas is available at retail stores. The quadrangle is defined within this publication by very fine cross-hairs. These can be very difficult to see amidst the map symbols and line so consult a page including a portion of Lake Erie where the marks are more visible. Using a straight-edge, draw lines connecting the cross-hairs in order to define your particular block.
