Lewis Alan Jones , Christopher D. Dean, William Gearty , Bethany Allen 

The geological record is a vast archive of information that provides the only empirical data about the evolution of the Earth. In recent years, concentrated efforts have been made to compile macrostratigraphic data into the online centralized database Macrostrat (https://macrostrat.org). Macrostrat is a global stratigraphic database containing information regarding surface and subsurface rock units and their respective ages, lithologies, geographic extents, and various other associated metadata. However, these data are currently only accessible through the Macrostrat application programming interface (API), which is a barrier to potential users that are less familiar with such services. This data accessibility hurdle currently prevents full capitalization of the value offered by Macrostrat, particularly its potential to improve understanding of the geological and biological evolution of the Earth. Here, we introduce rmacrostrat, an R package which interfaces with the Macrostrat database, to access and retrieve a variety of geological, paleontological, and economic data directly into the R programming environment. In this article, we provide details about how the package can be installed, its implementation, and potential use cases. For the latter, we showcase how rmacrostrat can be used to estimate the proportion of North American carbonate and siliciclastic sediments through time, produce regional geologic outcrop maps, and visualize regional stratigraphic columns. We hope that this package will make geological data more readily accessible, and in turn will facilitate new research utilizing Earth System data.