267 ISSN 0869-5938, Stratigraphy and Geological Correlation, 2007, Vol. 15, No. 3, pp. 267–276. © Pleiades Publishing, Ltd., 2007. Original Russian Text © S.O. Zorina, 2007, published in Stratigrafiya. Geologicheskaya Korrelyatsiya, 2007, Vol. 15, No. 3, pp. 32–41. The Middle–Upper Jurassic composite section of the northeastern Ul’yanovsk–Saratov depression has been characterized in the course of geological survey carried out seven years ago in the Sviyaga–Sura inter- fluve (Fig. 1). The section is represented by the beds succession typical of the Ul’yanovsk–Samara region. The beds are discriminated in accordance with unified stratigraphic charts for Jurassic deposits in the Russian plate, which were approved by the Regional Interde- partmental Stratigraphic Commission in 1993 (Explan- atory Notes…, 1993) and verified in 1994. The results of litho-, bio-, magneto- and sequence-stratigraphy are published, along with characterization of the Jurassic– Cretaceous regional formations, in a series of earlier works (Balabanov, 2004; Didenko and Zorina, 2003; Zorina, 2005a, 2005b). Stratigraphy of Middle–Upper Jurassic Deposits in the East Russian Plate S. O. Zorina FGUP “Central Research Institute of Geology of Industrial Minerals,” Kazan, Russia Received January 17, 2006; in final form, August 29, 2006 Abstract—The work is aimed at litho-, bio- and magnetostratigraphic subdivision of the Middle–Upper Juras- sic sedimentary succession in the northeast of the Ul’yanovsk–Saratov depression (the East Russian plate). Problems of regional and interregional correlation of distinguished subdivisions are considered. As is shown, the ammonite biostratigraphy is most effective method for solving problems of chronostratigraphy. DOI: 10.1134/S0869593807030033 Key words: Middle–Upper Jurassic, Russian plate, ammonite zones, biostratigraphic units, Boreal zonation standard. Fig. 1. Geographic positions of the considered drill hole sections (numbered) within the study area (black contour). Well 4 Krasnyi Klyuch Syundyukovo Tarkhanovskaya Pristan Volga R. Ul’yanovsk 50 km 48° 0 Tatarskie Shatrashany Well 1 Maloe Nagatkino Well 3 Well 2 Tatarskaya Bezdna Staroe Drozhzhanoe Sviyaga R.