Harold G. Coffin is a palaentologist and creationist (and signatory to the CMI list of living scientists who accept the Biblical Accountof Creation). He has some publications in regular journals, none of which support creationism, but has also written a slew of creationist articles for creationist journals, for instance on how the origin of coal may support a Catastrophic Flood theory. The argument consists pretty much of identifying a potentially unanswered question in modern geology and inferring from this that Flood geology must be better. His creationist ad hoc interpretation of polystrate fossils has not been accepted by mainstream scientists either, to put it mildly, though Conservapedia is apparently impressed.
Coffin witnessed during the McLean vs. Arkansas Board ofEducation trial, where – among other things – he admitted that were it not for the Bible he would have believed that the earth was very old, which is (though creationists may deny it) a straightforward admission of how much creationism has to do with science (also here).
Diagnosis: One of a frighteningly huge number of influential figures in the fight against reason, Coffin is neither the most aggressive nor the loudest. That doesn’t entail that he is not dangerous, however.