Having read most of the book, I would like to point out that tusks were found in other areas that were also peppered with iron bits. In addition, when the authors went to various Clovis sites to try to determine if the Clovis people were killed off by a comet crash, they ran a strong magnet up and down the sides of the excavation cuts. Large numbers of iron particles were attracted right at the Clovis level, and much less before and after. This test was done at a number of Clovis sites, and also at the Carolina Bays, always with the same results. The book is quite interesting for those with a scientific turn of mind, as they go into great detail as to how and where they conducted their rather convincing research.
Well put.