ABSTRACT
T h e end o f the winter, the spring and early summer is in Britain the best time for archaeological air reconnaissance. The quantity and ränge o f information then recoverable is vast. In the late
winter and early spring long shadows east by a low sun emphasize minor differences in relief, scarcely to be appreciated by an observer on the ground, while soil pattems in freshly ploughed land which show where disturbances have taken place are then seen to best advantage. In spring and early summer, differences in colour, density or luxuriance o f growth commonly develop in response to hidden differences in the soil. These “ crop-marks” , as they are termed, reveal to an observer, often in the finest detail, buried remains o f which no trace can be seen on the surface.
