All good things must come to an end, and the reign of the dinosaurs is nearly over. A comet is heading for the planet, and the Sinclair family gather to meet their end.
This is a heartfelt, tearful ending that really isn't appropriate for all fans. Though the season finale, during the original TV run several episodes were aired afterwards. So if you wanted to, you could view it as a "what-if" that never happened, and keep watching.
Sadly though, it does spell the end of the series, and the Sinclair family we've come to know and love. Good bye dinosaurs!