A geologist's field book is often a yellow or orange, bound or spiral book about 4⅝ by 7½ inches in size, with lined, columned, or gridded paper, often waterproof. The first thing a geologist writes in his or her field book on any given day is the date. The second thing a geologist writes is the place — town, mountain range, mining property, reconnaissance target, township and range (or UTM coordinates if you are using an up-to-date coordinate system), country, county, river, sampling area, name of the field trip you are on — whatever is the most relevant and identifying locality title or place name for that current subsection of your notes. The third thing a geologist usually writes (at least if you were taught back in the 1970’s or earlier) is the day’s overall weather.
Related Geoblogospheric Posts:
Tools of the Trade
Field notebook for the office
Stack of field notebooks
What to Buy a Geologist for Christmas