A paleomagnetic investigation was carried out on oriented samples from two regions, the NE. and SW. parts of the Inner Sudetic basin, and from the Kladno-Rakovnik and Plzen basins some 200 km distant on the Bohemian platform. The directions of remanent magnetization from the two areas after magnetic cleaning (using both thermal and alternating field techniques) were significantly different. As the rocks examined can be shown to cover the same time interval, from Westphalian B/C to the end of Stephanian, it is suggested that the difference may be due to subsequent tectonic effects, and consideration of the results suggests that the Bohemian platform was the region affected. Geophysically the result suggests that tectonic effects may be an important cause of virtual pole dispersion; geologically it suggests the need for caution in paleomagnetic interpretation.