In Jiepaiyu area, Shimen County, Hunan Province, there exist a number of top-like breccias, which occur either in groups or as isolated ones, constitute steep ridges or hills and usually take elliptical or isometrical forms at surface and conical or cylindrical forms branching upward in profile, with the branches exhibiting stock, dike or irregular forms.On the basis of formation characteristics of top-like breccias, it is believed that these toplike breccias are of hot spring origin. Silicalites in the top-like breccias are most probably silica sinters deposited from hot spring water. Trace elements in breccias are similar to those in sedi- ments from modern hot springs. A rock-forming model for top-like breccias of hot spring type is proposed in the paper: circulating, migrating in strata and heated by the deep thermal flow system, the percolating meteoric water might extract ore elements and mineralizing agents from the strata, producing ore-forming fluid. when this fluid ascended along faults, explosive breccia and karst breccia were formed as a result of drastic explosions of hot spring gases and related substances under the sealed and reduced conditions.Various breccias may yield large-sized uranium deposits, gold deposits, polymetallic deposits and realgar deposits. The largest realgar-orpiment deposit ever discovered in China occurs in these breccias. The top-like breccias may serve as excellent ore-hosting and ore-controlling geological bodies and hence have important ore-prospecting significance.