From a hydrologic point of view it is worth mentioning the presence of Vârfurașul spring, of the temporary dry section of the Valea Seacă stream between the swallet "de la Tău" and Nimoioasa springs, and the karstic stream piracy features along Valea Podurilor. Several caves and potholes have been explored, among which the outstanding 2250 m long Vârfurașul cave (Kőmíves & Nagy, 1976).
The Vârfuraș cave is an active multileveled system, morphogenetically belonging to the type of latural digressive caves, mainly formed in epiphreatic regime conditions, determined by the amount of deepening process of the surface streams. Vâfuraș cave excelling in number, dimensions, colour and variety of montmilk, calcite and aragonite formations. Two are the most significant potholes: "cu Spinare" and "Mare", placed in the isolated zone known "Fundu Muntelui", in the fountain-head area of Seacă valley, being the farthest sink known, developed in a small window of this particular covered karst, belong to the Vârfuraș system.
Two smallest karst area are also tributary of Pârâul Stanciului: streams from Lespezi and Arsă peaks. There are isolated eastward from Valea Seacă, in the left respectively in the right of the main stream. The most developed cavities are shortest then 1 km: Lespezi 2 cave, Izbucul Lespezi cave and Lespezi pothole formed perhaps by the water of Fetițași stream.
There are presented two fluvial absorbtion type of potholes (SPINARE p: Length = 279 m, vertical elevation = -72 m; MARE p: Length = 73 m, vertical elevation = -60 m), located in the Upper Bassin of the Seaca Valley (Vladeasa Mountains) area known as Fundu Muntelui. Both have a rather simple morphology, being developed on quasivertical joints in partially metamorphosed Upper Jurasic (Tithonian) limestone. The importance of these potholes lays in the fact that they belong to the Varfuras system, being the farthest sink known, developed in a small window of this particular covered-karst.