Have we observed aliens? No.
Has time travel, backwards, been observed? No
And have we found Deinonychi in enough quantity to justify the idea that they had a culture? No. (Remember, they could have made their tools with wood, but they would have left, at least, their skeletons). And have they been found close to the remains of the creatures they supposedly took across the oceans? No. And have we found any creature that had the ecological sense to carry all living things, including plants, predators, herbivores so big that it was impossible to use them as food?
Even we, humans, have never even attempted moving such enormous amount of different flora and fauna, enough to populate a continent or two. And remember, the geological strata also matches. Did the Deinonichi also carry geological strata in their 4 meter rafts?
All I ask of you is that you believe in one unobserved phenomenon, be it space travel or time travel. And yes, it is too much to ask.