In a previous publication, an iridium anomaly was reported in core RC9--58 from the Caribbean Sea, about 30 cm below the peak abundance of North American microtektites. In order to determine more precisely the relationship between the iridium anomaly and the North American microtektite layer, we searched for microtektites in the samples that were used for the iridium studies. We found that the North American microtektite layer is actually two layers, with the peak abundances separated by 25 cm. The upper layer consists of 'normal' North American microtektites and the lower layer consists of previously described clinopyroxene-bearing spherules. The iridium anomaly was found to correlate with the lower layer. Although the two layers appear to be the result of two separate events, several lines of evidence suggest that they were produced by a single event. The separation into two layers may have been produced by differential settling in the sediment due to density variations. The correlation between the iridium anomaly and the North American microtektite layer supports the terrestrial impact origin for tektites.