The Petøkovice Mem ber is the basal unit of the paralic suc ces sion of the Ostrava For ma tion of the Up per Silesian Ba sin. This mem ber is a valu able source of in for ma tion about the tran si tion from a ma rine ba sin filled with siliciclastic sed i ments into a paralic ba sin with the be gin ning of coal-bear ing sed i men ta tion. Mod els of: (1) the num ber of coal seams, (2) their to tal thickness, and (3) the coal con tent with re spect to the to tal thick ness of the suc ces sion were cre ated to de scribe and as sess the coal-bear ing ca pac ity of the Petøkovice Mem ber. The au thors pres ent mod els for coal seam thick nesses ex ceed ing ei ther 10 or 40 cm. The coal-bear ing ca pac ity of the Petøkovice Mem ber is very low. The av er age share of coal seams thicker than 0.1 m is 3%. The share of coal seams with a thick ness that ex ceeds 0.4 m is only 1.66%. More over, in large ar eas of the basin, in the N and NE parts, the coal-bear ing ca pac ity is close to zero, be cause coal seams of greater thick ness were de tected only lo cally there. Based on these mod els and on other geo log i cal data, it is ob vi ous that the on set of coal sed i men ta tion was grad ual and lim ited to par tic u lar sites show ing the great est sub si dence of the ba sin floor. In places where mi nor sub si dence took place, there were likely un fa vor able con di tions for ac cu mu la tion of or ganic mat ter.