The evolution of Gajina mlaka paleovalley from pre-karstic to current phase reveals the complexity of process of transformation of valleys in karst and formation of fluviokarst uvalas. The creation of river network and formation of the valley of Gajina mlaka are related to successive withdrawal of the Pontiac Sea. Predominance of karstic process over fluvial causes the transformation of fluvial morphology into karstic. The degree of transformation depends on relationship of the intensity between these two opposed processes. Karstification covers all parts of Gajina mlaka valley which are built in karst. Riverbeds are almost completely transformed and dolines are formed along them. In the parts of valleys with more significant lithologic differences, more complex tectonic relationships and different pre-karstic fluvial morphology, larger forms of relief are created by karstic process and they are called uvalas. According to the presented method of genesis and evolution of uvalas it can be concluded that they are clearly morphologically and genetically individualized karst landforms, which negates some contemporary opinions that exclude both the term and form uvala as karstic element of relief.Evolucija paleodoline Gajina mlaka od prekraške do savremene faze otkriva složenost procesa transformacije dolina u krasu i nastanak fluvio-kraških uvala. Nastanak rečne mreže i stvaranje doline Gajina mlaka vezan je za sukcesivno povlačenje Pontiskog mora. Prevaga kraškog procesa nad fluvijalnim dovodi do transformacije fluvijane morfologije u krašku. Stepen transformacije zavisi od odnosa inteziteta ova dva suprostavljena procesa. Karstifikacija zahvata sve delove doline Gajina mlaka koji su izgrađeni u krečnjacima. Rečna korita su gotovo u potpunosti preoblikovana i duž njih se formiraju vrtače. U delovima dolina sa značajnijim litološkim razlikama, složenijim tektonskim odnosima i različitom prekraškom fluvijalnom morfologijom kraškim procesom izgrađuju se veći oblici reljefa - uvale. Iz prikazanog načina nastanka i evolucije uvala proističe da su one jasno morfološki i genetski individualisani kraški oblici, čime se negiraju pojedina savremena shvatanja koja isključuju i termin i oblik uvale kao kraškog elementa reljefa
