All researchers note the wide distribution of Ordovician sediments in the area of the Western Sayan, although the volume and structure of sediments attributed to the Ordovician are understood in different ways. In spite of sufficient geological study of the territory, the number of locations of remains of reliable Ordovician fauna is still measured here in units. One of these localities is the Karyn-Sug river. Karyn-Sug (according to I. B. Filippova) is located in the central part of the Western Sayan, the other two - the Manchurek River, the upper Manchurek River, and the upper Manchurek River. Manchurek River and the headwaters of the Ak-Sug River are located on its south-western edge, within Tuva. Locations of Ordovician fauna are also described on the northern and northeastern margins of Tuva - in the area of its interface with the Western Sayan ...