Located twenty five miles off the southern coast of Mount Desert Island, Mount Desert Rock is home to the second research station of College of the Atlantic. The “Rock” as it is known is host to marine mammal research and the Allied Whale Organization. Mount Desert Rock is entirely composed of a medium grained (phaneritic) granite. Of interest is the extremely high quartz content. (See Figure x)

 

       In comparison to both Great Duck island and Mount Desert island the granite of the rock is a light gray. Although it it also contains potassium feldspar it is more likely microcline. Lastly, it is extremely Felsic. This has direct consequences to the weathering and erosion processes in effect on the island. The Rock frequently, if not constantly, is pounded with heavy surf and wind. It is completely exposed without any vegetation of overburden. As a result, the bedrock bares the brunt of any erosion. At surface temperature and pressure Mafic minerals are the first to weather out and weaken the rock. Mafic minerals are those that contain iron and magnesium such as biotite and hornblende. The granite of Mount Desert Rock contains almost none of these. Consequently it is extremely resistant to these weathering processes.