Oak apples?

At the top of the hill there are several small oak trees in the hedgerow. These small, spherical growths on some of the twigs are what I've always known as oak apples, but having pored over several websites this evening, I'm still not sure if they are oak apple or oak marble galls. They are mostly brown, and spherical, which probably suggests the latter. Expert advice and correction are always welcome.

I walked briskly up the hill before lunch because there was a pause in the rain, which has persisted for most of the day. It was damp, drizzly and very windy, so most of my hedgerow photos suffered from motion blur - a pity as the rampant brambles are now covered in vivid new green shoots unfurling between the old leaves, and the buds on the blackthorn are just starting to open into delicate blossom. There are wood anemones under the trees in our friends' hillside wood, too far away to photograph well, and between them the year's first bluebell buds are just visible. As I turned to descend, the rain became heavier and more persistent - a couple of landscape photos were dotted with blurry raindrops, and I returned home quite wet, but glad of the air and exercise.