Grammar. The development of geology owes much to the work of non-professional observers. In no other science, with the possible exceptions of astronomy and archaeology, has the keen amateur participated so actively or contributed so much. This is mainly because experimental methods of investigation involving complicated apparatus typical of chemistry, physics and biology are of only limited use in geology, which results from the fact that geological processes work slowly and depend on factors beyond human control. The advance of geological knowledge has depended on simple observations, patiently gathered, of the outcrops of rocks, their thicknesses, their angles and their fossil content
