Initial assessments of the potential for geologic carbon sequestration rely on existing subsurface data, most of it collected for oil and gas exploration. We document the challenges of assessing the storage potential based on archived data, for the case of the Upper Ordovician Queenston Formation in New York. In central New York, the entirely subsurface Queenston Formation consists primarily of sandstones. In contrast, in western New York where the Queenston Formation crops out, it is composed of shale, siltstone, and sandstone. A foremost interpretation challenge is to obtain porosity data from the borehole logs. Intercomparisons of various measures of porosity and of the availability of those data led to the decision to use neutron porosity data for the hematite- and clay-rich sandstone. To map porosity regionally, a second challenge is to establish the physical correlation between four regionally extensive stacked petrophysical zones in central New York, each recording base-level fall trends in fluvial sandstones, and four petrophysical zones in western New York, each characterized by base-level rise deposits of marginal marine and shallow marine deposits. Two alternative correlations can be justified with differing implications for pore volumes in a transition region. This analysis estimates that the Queenston Formation of central New York can sequester up to approximately metric tons of at depths greater than 3000 ft (914 m) in sandstones with porosity exceeding 10%. The Queenston Formation is not suitable for storage in western New York.