Bryum coronatum was described from Guiana and Jamaica by Schwaegrichen (1816) but is known to have a rather wide distribution in the warmer parts of the world. In the US it has been reported only from Florida. While at the UMBS the authors in late June 1959 visited limestone sink no. 4S2 of the series whose bryophyte flora was studied by Robinson and Wells (1956). On a moist, calcareous ledge of a wall of the sink a Bryum was collected, in fruit, by the senior author. This was soon identified as B. coronatum, and later Dr. A. L. Andrews kindly confirmed this determination. Although the Mihigan plants have slightly smaller leaves and somewhat smaller leaf cells than the material from other parts of the world, the differences seem to be slight to be significant. We believe that this collection represents not only an extension of range of nearly 1000 miles to the north in North America and the first record of B. coronatum in Michigan but also the first report of it from a cool temperatre area. For mapping purposes, the sinks are located in northern Alpena County. An explanation of its occurrence there awaits further study. Exsiccati (no. 141) of this material are deposited at the U. of Tennessee and the U. of Michigan and in the herbarium of Dr. A. L. Andrews.