In the summer of 1935, the author collected material on the mineralogy of pegmatite veins located on the northern slope of the Gissar ridge in the Kara-su river basin and partly in the Ak-su (Khanaka-su) river basin. The results of processing this material form the content of this article. The author's task did not include a special study and study of the pegmatite veins of the region, but only required an examination of the veins from the point of view of the presence of tin-containing minerals in them. Nevertheless, the collected material turned out to be sufficient for the general mineralogical characteristics of the pegmatites of the region, genetically related to porphyritic granite. Based on all that has been said, it must be assumed that the Central Gissar granite batholith gave rise to certain pegmatite fields. Among the pegmatite bodies there are pegmatites with tin stone. Therefore, the study of pegmatite formations associated with the Gissar batholith should continue. The deposit of tin veins along the river Kara-su should also be studied and explored. Taking into account the above considerations, cassiterite content in these tin veins should be expected to increase with depth. It should be noted that the sharp relief, as well as the frequent natural camouflage of pegmatite veins, all complicate prospecting and exploration work in these areas. But this of course should not confuse researchers.
