Potential sources of breakwater construction material in the area surrounding Port MacDonnell have been investigated. Deposits of dolomite, basalt and flint pebbles in the area were inspected, and the presence of granite near Dergholm in Victoria has been noted. Samples of olivine basalt from the quarry at Mount Schank were submitted to the Highways and Local Government Testing Laboratories, and to the Australian Mineral Development Laboratories. Testing of these samples has yielded encouraging results. At this stage in the investigation the quarry at Mt. Schank appears to be the most promising source of material, but more detailed specifications are needed before a final conclusion can be reached. Further exploration required to define each site is nominated.