42 
AMERICAN JOURNAL 
NOTES ON MOLLUSCA OF MONTERET BAY, CALIFORNIA. 
BY J. G. COOPER, M. D, 
Monterey is situateci in lat. 36° 36', on nearly thè same pa- 
rallel as Norfolk, Va., Cadiz, Spain, and thè northern part of 
Niphon, Japan, and has of late become quite noted aniong those 
interested in thè conchology of western North America, as an 
excellent locality for obtaining a large variety of species both of 
thè northern and southern temperate groups. Its situation and 
locai conditions are perhaps better suited for producing a large 
number of marine species of mollusca than those of any other 
point on thè coast of temperate North America. It has thè ad- 
vantages of an insular and a Continental station combined. 
Topography AND Hydrography. 
The harbor of Monterey facing north and receiving a Constant 
but greatly moderated ocean swell, broken by thè promontory 
of Point Pinos, has no large influx of fresh water nearer than 
thè Salinas river, 17 miles northward. The rock forming thè 
shore west of thè town is granite for three and a half miles, and 
by disintegration has made a beach of clear white sand, extending 
nearly around thè bay, a distance of 70 miles. For about half 
this distance sand hills border thè shores, succeeded by cliffs of 
Soft post-pliocene sandstone, which border thè north end of thè 
bay at Santa Cruz, 25 miles directly north of Monterey. This 
sandstone also overlies thè granite from near low-water to eight 
fathoms depth, a mile northeast of town, forming a rocky bottom 
for some distance off shore, and prevails throughout a large part 
of thè north end of thè bay. 
Monterey has thus thè conditions for preserving that salt- 
ness and clearness of thè water necessary for most marine 
shells, together with a variety of stations suited for various 
species, hard, immovable granite, soft sandstone for borers, 
sand, and at 30 fms., mud. The estuaries, so numerous along 
thè coast, especially northward, are all more or less influential 
in diminishing thè number of species elsewhere, and even at 
