A teacher's weekly notes on her natural surroundings in city and country make a kind of simplified ""Walden"" and may serve as an inspiration to deeper, closer observation. Dividing her time between New York (where she teaches creative writing at Columbia), her week-end house up the Hudson and Maine in the summer, the author has made her own almanac of weekly notes on animals, plants, the weather and seasonal changes- with plenty of room for ideas about other things in life. Starting in January she notes, along with the sunset, that winter makes her feel ""more a part of the wide earth than when the green leaves close around...and makes us into a quiet island."" In February, with its four evenly spaced weeks, she wonders why man has not divided his year that way, and so on. Reflective and scientific, this may prove absorbing for the interested and exemplifies a good exercise in writing.