The quality of early turnpike roads was varied. Although turnpiking did result in some improvement to each highway, the technologies used to deal with geological features, drainage, and the effects of weather were all in their infancy. Road construction improved slowly, initially through the efforts of individual surveyors such as John Metcalf in Yorkshire in the 1760s. British turnpike builders began to realize the importance of selecting clean stones for surfacing while excluding vegetable material and clay, resulting in more durable roads.