CHRONOS's purpose is to transform Earth history research by seamlessly integrating stratigraphic databases and tools into a virtual on-line stratigraphic record. In this paper, we describe the various components of CHRONOS's distributed data system, including the encoding of semantic and descriptive data into a service-based architecture. We give examples of how we have integrated well-tested resources available from the open-source and geoinformatic communities, like the GeoSciML schema and the simple knowledge organization system (SKOS), into the services-oriented architecture to encode timescale and phylogenetic synonymy data. We also describe on-going efforts to use geospatially enhanced data syndication and informally including semantic information by embedding it directly into the XHTML Document Object Model (DOM). XHTML DOM allows machine-discoverable descriptive data such as licensing and citation information to be incorporated directly into data sets retrieved by users. ?? 2008 Elsevier Ltd. All rights reserved.