Cressida Connolly: Found dinosaur in field - another reason for not starting new novel

Two of the best, most child-friendly museums in England are in Oxford: the Pitt Rivers and the Oxford University Museum. They're in the same building, so you can wander through dinosaur skeletons, past a rather mothy, stuffed aardvark, to the mummies and shrunken heads and Inuit canoes in the Aladdin's cave which is the Pitt Rivers collection.

We had a special reason for our latest visit. A month earlier, we had taken in some fossils we'd found for identification. My nine-year-old son loves fossils and has quite a good collection, including some beautiful leaves in slate and two chunks of coprolite, which is fossilised dung. We've collected belemnites in France and a nautiloid at Lyme Regis. Last Christmas we gave him a woolly mammoth tooth, which looks exactly like a hefty piece of over-cooked roast beef.

Luckily, our farm borders the river Avon. About 200 million years ago, this land was under the sea. You can find fossils in the fields here, especially at this time of year, after the plough has turned the soil. Mostly they're gryphaea, the rather ugly, horned bivalves known as devil's toenails; or fragments of ammonite, the ridged spirals which most people think of when they think of fossils.

Then we found a stone disc a few inches across, indented in the middle. We took it into the Oxford Museum (which is really a natural history museum) along with a smooth, crescent-shaped piece that looked like bone, found in the same spot the year before. It turns out that we're practically living in Jurassic Park: the bone is the eye-socket of an ichthyosaur - a pre-historic dolphin-like creature - and the disc is one of its vertebrae. We felt pretty damn clever. "If there are more such bones in a localised area this find may be significant," said a note from Paul Jeffrey, the assistant keeper of geology.

So that was how my week began, tramping round the outskirts of a muddy field with my son, heads down, looking for more. Call me a snob, but an ancient marine reptile is just more exciting than a mollusc: it ups the ante. We found we could no longer be bothered to pick up bits of ammonite which would have thrilled us before the ichthyosaur. And although we found one piece which may (or may not) be bone, we both felt dejected not to be stumbling upon an entire skeleton. I fear we've been corrupted by success.

We live only a few miles from the village where The Archers is supposedly set, but I don't believe any of the residents of Ambridge have yet joined the Palestine Solidarity Campaign. In real life, however, a group of us meet once a month in Cheltenham. During the summer we had 10 Palestinian refugee children to the Cotswolds for a holiday. Last week we went on an outing to see the documentary, Jeremy Hardy v the Israeli Army, about the comedian's experiences with the international volunteers who travel from all over the world to help the people of Palestine.

I've been writing a book, a sort of group biography, about the Garman family, one of whom was the mother-in-law of Laurie Lee. I've got to know Lee's widow, Kathy, who is an exceptionally bright woman, outspoken and very funny. Kathy still lives near the village pub which her husband made famous, and which now stocks an ale named after him. When the pub came up for sale, the artist Danny Chadwick bought it. It's the only pub I've ever liked, old-fashioned without being whimsical. They serve pints of prawns, which is a plus. I was meant to be having lunch with Kathy Lee on Tuesday, but my 12-year-old got a bug and was off school.

While I was submerged in writing this biography, I longed to return to fiction. The trouble with real life is that people do inconvenient things and spoil their own stories, whereas the characters in fiction can live or die at will, just for the sake of the plot. I've been itching to start on a novel and now that I've finished the non-fiction book, I'm free to do so. This meant that I spent most of the week doing displacement activities, in order to avoid the starting fence. I made Christmas cake with the children, did some clutter-clearing, made lots of unnecessary telephone calls and pretended to do research for the novel on the internet. I'll be making a proper start this week. Probably.