Published by the American Geophysical Union as part of the Field Trip Guidebooks Series, Volume 305. This field trip was conceived as a way to introduce one of the major volcano-tectonic features of the North American continent to visiting scientists from abroad. Its objectives are to allow the participants to observe first hand the geologic relationships relevant to the formation of the Snake River Plain (SRP) and to discuss various interpretations of SRP genesis. The approach to these objectives is to travel the length of the plain from northeast to southwest and to examine in a logical manner, from younger to older volcanic rocks, the relationships important to an understanding of its origin and evolution (Fig. 1). Even though basaltic volcanism is commonly thought of in association with the SRP, this field trip will emphasize the importance of silicic volcanism because of its much greater volume and because of its profound effect on the upper crustal structure of the SRP.

Masters Theses in the Pure and Applied Sciences was first conceived, published, and disseminated by the Center for Information and Numerical Data Analysis and Synthesis (CINDAS) * at Purdue University in 1 957, starting its coverage of theses with the academic year 1955. Beginning with Volume 13, the printing and dissemination phases of the activity were transferred to University Microfilms/Xerox of Ann Arbor, Michigan, with the thought that such an arrangement would be more beneficial to the academic and general scientific and technical community. After five years of this joint undertaking we had concluded that it was in the interest of all con cerned if the printing and distribution of the volumes were handled by an interna tional publishing house to assure improved service and broader dissemination. Hence, starting with Volume 18, Masters Theses in the Pure and Applied Sciences has been disseminated on a worldwide basis by Plenum Publishing Cor poration of New York, and in the same year the coverage was broadened to include Canadian universities. All back issues can also be ordered from Plenum. We have reported in Volume 32 (thesis year 1987) a total of 12,483 theses titles from 22 Canadian and 176 United States universities. We are sure that this broader base for these titles reported will greatly enhance the value of this important annual reference work. While Volume 32 reports theses submitted in 1987, on occasion, certain univer sities do report theses submitted in previous years but not reported at the time.