this is a fun movie, and one I wish I had seen as a kid. it features four boys on a most unusual river rafting trip. there are a lot of dinosaurs to be seen, along with various other animals. Karel Zeman made it for those wild and crazy people in Czechoslovakia, and it was brought over here in the mid sixties.
I didn't see it until the 90s though, as it never aired in my area. with the release of Jurassic Park, dinosaurs rose to eminence again and the movie was released on LP VHS. it was $10 in a clamshell case. I greatly enjoyed it at the time. I wish a better copy was available on DVD now, as the sound in the second to last reel was out of sync completely.