There are books of the original movie. There are quite a few books containing little land before time stories which are not part of the movies.
Over here in Germany there are books of the original movie and two which also contain LBT 2 and 3. There are not those books with the little stories over here, but there were six audio plays based on these stories sold over here.
books give greater detail.
Maybe it is the other way round. Movies give more detail on how everything looks. One could write many pages just to describe the background and details and everthing shown in a TV scene. A book won't bother for example to mention that there is a pen lying on the table in the background unless the pen is of any importance. So while the book doesn't mention the pen it is up to the reader to decide what the place superficialy described in the book is looking like.
However, there are also things the movies cannot show clearly (thoughts, emotions, motivations etc.). While they can play with facial expressions or (in rare cases) with character monologues books are usually better in telling about the things which you can't see.
We don't tend to watch movies that take as long as it would to read a book telling the story of the movie (provided we are talking of somebody reading at normal speed). So very often the movie makers (have to) cut out details. This is indeed where books do give greater detail, whenever such cutting was necessary.
