Presumably the title of the episode is a reference to the giant turtle shell used by the humans, first as a boat and then as an air-holding diving bell.

As she, Katie, and Lok head off in a boat to find a nearby hermit who may know a way out of the valley, Kim tells John, who's about to go hunting with Gorok, that they'll be back in time to help skin the Plateosauruses or whatever they kill. Plateosaurus was a bipedal herbivore from the late Triassic period.

The cave dwellers refer to the wild boar as "begido".

John makes the remark "...if the high school faculty could only see me now." We know from "Forbidden Fruit" that John was a science teacher; this comment implies he taught at a high school.

As the boat courses down the rapids at 2:33 on the DVD, Katie's lips nearly fall off her face!

The creature referred to "kodo" by Lok appears to be a type of plesiosaur.

At 4:16 on the DVD, a small Pteranodon flies through the jungle.

The hermit tells Kim and Katie that the exit from the main valley lies through the valley of the Three Giants, three large rock formations.

Gorok refers to the Tyrannosaurus (John's identification) that lives in the valley of the Three Giants as Godon. But, when we see it, the beast has four claws on its forelimbs, eliminating it as a tyrannoaurid, which has only two. However, in "Rogue Rex", a tyrannosaur also referred to as Godon is depicted accurately (though both here and later in "Rogue Rex", the Butlers seem to be hearing of Godon for the first time). Still later, in "Saber-Tooth Kids", Gorok refers to what appears to be the same species (as presented here) as "zondi".

When Gorok warns the Butlers of the danger of Godon in their attempt to escape the Valley of the Dinosaurs, John remarks that there have been dangers every time they've attempted to escape. This implies the family has made a number of escape attempts, but this this is the first one we've seen.

Heading down the river in their upturned giant turtle shell, the Butlers encounter a few flying frogs. There are actually thousands of species of flying frogs in the modern world, an adaptation to tree living.

The pterosaur seen at 6:36 on the DVD appears to be a Rhamphorhynchus.

The creature referred to as an "odall" by Gorok, at 6:46 on the DVD, appears to be a type of long-necked plesiosaur.

Digger and Glump run up a slanted tree trunk that turns out to actually be the tail of a giant sauropod at 7:46 on the DVD. The sauropod appears to be some type of brachiosaurid. The scene is somewhat reminiscent of the opening titles of another Hanna-Barbera production, The Flintstones.

Lok tells John that Godon sees better in the dark than the saber-tooth. This is a reference to the saber-tooth cat, species of which existed from 42 million to 11 thousand years ago. However, there is no evidence to suggest that a (alleged) tyrannosaur could see better at night than a species of saber-tooth cat.

John tells Gorok and Lok of the bronze shell used by Alexander the Great (356-323 BC) as a submersible for exploring the sea floor around Greece, the first known primitive version of a submarine. This is true, though it is described as a glass submersible, not bronze, by Aristotle (384-322 BC). 

When Greg seeks a spear to use against Godon, Tana points him to a plant with a very sharp point at 14:57 on the DVD. It appears similar to the century plant (Agave americana), which were used as spears or spear tips by natives of the Americas. But Greg uses the base of the stem as the point of his spear and the actual century plant has the deadly point at top.

As the group races for the lake, Greg shouts, "Last one in's a Dodo bird!" The Dodo was a large (over three feet tall as adult) bird discovered on the island of Mauritius in the Indian Ocean in the late 16th Century and which was made extinct by human presence less than a century later.

Memorable Dialog 

if the high school faculty could only see me now.wav

anything that ugly.wav 

how he smells.wav