Good article from CMI. I'm posting it for fellow Creationists, and really for anyone else who is interested.
"After the Flood, the marsupials left the Ark and dispersed around the world. They could have dispersed before many of the other mammalian varieties. They occupied various niches around the world, but were eventually driven off by competition in Europe, Africa, and Asia. Finally, they ended up establishing themselves in more distant (vis-ŕ-vis the Middle East) regions. As ocean levels rose at the end of the Ice Age, land bridges were eliminated and the migrant marsupials were stuck where they were.10 There’s also evidence suggesting that human travellers introduced some of the marsupials to distant lands, which can explain conundrums of very similar marsupials in different parts of the world.11"
"Significant disjunctions are also found in the fossil record. For example, many similar plant fossils are found in western North America and eastern Asia but, according to the ancient earth geologists’ account of slow continental drift, these rocks were laid down when Alaska and Russia were still thousands of kilometres apart.13
While living marsupials14 are largely restricted to Australia and South America (opossums), their fossils from rocks classified as Late Cretaceous (supposedly between 85 and 65 million years old) are found exclusively in Europe, Asia and North America. Richard Cifelli, an associate professor in the Department of Zoology at Oklahoma University said, “this geographical switch remains unexplained.”15 Interestingly, fossil marsupials have now been found on every continent.16,17"