The main goal of the master thesis was to investigate geologic sites from where stone material used for construction of the Roman settlement Aquae Iasae in Varaždinske Toplice was possibly exploited. This was achieved by comparing petrographic characteristics of the main limestone types formerly analysed as building blocks in the Roman settlement (HORVAT, 2011; ALJINOVIĆ, 2015) with rocks from the two outcrops in the vicinity of the archaeological site suggested as potential ancient quarries by archaeologists working on the excavation and preservation of the site. Two outcrops were investigated - Bela Pećina and Slap from where 24 samples were analysed. Additionally, 4 samples were micropetrographically analysed that represented type of limestone used for constructing the spring pool at the forum (samples marked AM-1 to AM-4). It was concluded that samples taken from Bela Pećina (samples marked as BP-1 to BP-14 along the 6,5 m thick sediment succession) and samples taken lateral from the succession (T-5-2 to T-5-7) correspond to Miocene (Badenian) bioclastic limestone (biosparite/biosparrudite)and only one sample was determined as fossiliferous sandstone (lithoarenite). The rocks samples from locality Slap (Slap-1, Slap-2, Slap-3) represent Miocene tuffs. Thirteen analyzed samples from the Bela Pećina were determined as biosparite/biosparudite that correspond well with formerly analysed limestone types. Thus, locality Bela Pećina (BP-1 to BP-13 and T- 5-2 to T-5-7), might have been the ancient quarry from where stone was exploited as building material in Roman times. A different type of limestone used for constructing the spring pool in the forum was determined as biomicrite, consisting of planktonic foraminifera and lime matrix. No exploitation site was proposed as ancient quarry of this limestone type. Locality Slap with differentiated vitriclastic tuffs was excluded from consideration as a potential site for stone exploitation in Roman times. All analysed limestone types used in the construction of Aquae Iasae, represent different facies and environment of their primary deposition. Biosparrudite and biosparite are interpreted as organic bioherms (reefs) or high-energy fore-reef environment, while biomicrite with planktonic fauna as deep and open marine, low-energy facies.