MICHIGAN ACADEMY OF SCIENCE. 
131 
RESULTS OF THE MERSHON EXPEDITION TO THE CHARITY 
ISLANDS, LAKE HURON. 
MAMMALS. 
N. A. WOOD. 
This paper is one of a series that is to appear on the flora and fauna 
of the Charity Islands, as a result of investigations made by the different 
members of the Mershon Expedition of the University of Michigan 
Museum. A general account of the expedition has already appeared. 1 
It is sufficient here to state that the work was made possible by the gen- 
erosity of Hon. W. B. Mershon of Saginaw, Michigan, and was carried 
on, during the late summer of 1910, by six men, each of whom gave his 
attention to a particular group. The writer had charge of the vertebrate 
work, and, although the island is almost devoid of mammalian life and 
most of his attention was given to the birds, 2 he made an effort to secure 
as accurate a knowledge as possible of the mammals. 
The writer wishes to acknowledge the assistance of the liglit-house 
keeper. Captain C. C. McDonald, and his assistant, Joseph Singleton, 
both in collecting specimens and in furnishing data on species which 
they have noted on the islands. Captain McDonald’s notes are particu- 
larly valuable for he has spent nine entire years on Charity Island 
and for twenty years has lived a part of each year there. 
The Charity Islands are situated near the mouth of Saginaw Bay, in 
latitude 44° north. There are three islands in the group. Charity Island 
proper contains about six hundred and fifty acres, Little Charity, the 
next largest, about three acres, and Gull Island is a small projecting 
reef, about a quarter of an acre in extent, that is not usually shown on 
the maps. The islands are somewhat nearer the west coast than the 
east. Charity Island is six and seven-eighths miles southeast of Point 
Lookout on the north shore, and nine and five-eighths miles northwest 
of Case vi lie, seven and three-fourths miles north of Sand Point, and nine 
miles northwest of Oak Point on the south shore. 
Geologically the foundation of the islands is Maxwell sandstone. On 
Charity Island this outcrops as ledges on the north and east sides, but 
it also appears on the other sides, especially on the points, which are 
bare rock. The surface is covered with sand driven up by the action of 
winds and waves into fossil beaches and sand dunes. The island is 
being enlarged continually by the addition of sand flats, especially on 
the west side, where a large bar of many acres in extent is now almost 
at the surface of the water. Little Charity Island is of much the same 
character, and Gull Rock is a low rocky islet covered with sand. 
Fortunately for our work, Charity Island is a light-house station, and 
hunting and fishing within one mile of its shores, and the cutting of the 
vegetation are not permitted. The conditions are thus quite primitive 
’Ruthven. Alexander G, Science, N. S., XXXIII, pp. 208-209. 
2 Wilson Bulletin, Vol. XXIII, pp. 78-112. 
