The 7th International Graptolite Conference and 2003 Field Meeting of the Subcommission on Silurian Stratigraphy is held in South America for the first time. Argentina was elected as host of these meetings at the 6th International Graptolite Conference by the Graptolite Working Group of the International Palaeontological Association in Madrid, 1998. San Juan City was the chosen venue for current meeting to succeed the six previous ones: Warsaw (1977), Cambridge (1981), Copenhague (1985), Nanjing (1990), Long Beach (1995), and Madrid (1998).
The organization of these meetings in conjunction with the 9th International Symposium on the Ordovician System (ICS-IUGS) gathered a significant number of researchers of the Lower Paleozoic from all over the world. In particular, over 65 authors and co-authors from numerous countries contributed with presentations to the 7th IGC and 2003 FMSSS during August 18-21, 2003, in San Juan. The scientific program was complemented by an intra-conference field trip to the San Juan River section, and pre- and post-symposia field trips to the Precordillera of San Juan and Mendoza, and the Cordillera Oriental and Sierras Subandinas of northwestern Argentina, respectively.
The Proceedings of the 7th IGC and 2003 FMSSS are published as a special volume (18) of Serie Correlación Geológica, INSUGEO, Universidad Nacional de Tucumán, Argentina, especially devoted to Historical Geology.
Present proceedings include thirty short papers and abstracts, most of them given as oral or poster presentations in the scientific program. A diversity of topics is covered by this volume; such as, graptolite taxonomy, peridermal ultrastructure, biostratigraphy, correlation, stratotypes, bioproductivity, and eustatic events. The volume is divided into two parts: The 7th IGC section includes papers on different Ordovician to Devonian graptolite issues, and the 2003 FMSSS section includes contributions on Silurian stratigraphy. Particular papers dealing with problems on the Ordovician-Silurian boundary are enclosed in this second part.
Manuscripts submitted by the authors for inclusion in present volume were thoroughly reviewed. The editors greatly appreciate the valuable work of the intervening referees. Likewise, we acknowledge the efforts made by the staff of the publisher “Editorial Comunic-arte” to get ready the publication for the meeting, and the constant advice during the production of this volume. We are grateful to Dr. Guillermo L. Albanesi (CONICET - Museo de Paleontología, Universidad Nacional de Córdoba) for his permanent assistance on the editorial work. Technical support was provided by the National Universities of Córdoba and Tucumán, and National Academy of Sciences at Córdoba. A special support for the organization of the 7th IGC and 2003 FMSSS was given by the “Agencia Nacional de Promoción Científica y Tecnológica” (Argentine Government).
With the hope this volume projects to the future the long standing tradition on exciting graptolite studies.

Sincerely, the editors, Gladys Ortega and Guillermo F. Aceñolaza
August, 2003