506 Walks Round San Francisco—The Bay Shore. [ August, 
they recede. In the far distance a thin line of smoke marks the 
position of a steamer ez route to or from San José. 
The shore of the bay in our vicinity is much indented by rocky 
peninsulas alternating with valleys, the outlets of which are filled 
either with a marsh or a lagoon, produced by the little streams 
that find their way from among the round-topped hills. Hunter's 
point, which is in our rear soon after we leave the cars, runs out 
into the bay two or three miles, then follows a marshy tract on 
which are placed the butts of a rifle company, then an isolated 
mound rising close to the edge of the bay, then a valley with a 
lagoon, and south of this, a lofty hill with serrated outline ter- 
minating baywards in a precipitous promontory, with a needle- 
rock as an outlier. This lagoon, the serrated hill and the beach 
around it are our hunting-ground to-day. We are armed with a 
spade and intend to dig for clams. Luckily it is low tide, a large 
area of silt is uncovered in front of the lagoon, and we hasten 
onwards to try our chances. Not that there is much risk of 
missing the clams when they spout beneath the feet at every step, 
and when every spadeful throws up at least two or three, The- 
most abundant clam at this spot is the ubiquitous Mya arenaria, 
which also has possession of the entire beach near Oakland, on 
the Alameda county side of the bay; but the native Californian 
Schizotherus nuttallii, a monster of a clam when full grown, reach- 
ing.a length of about seven inches, is also found here deep in the 
mud. Its ugly black siphon is as thick as a finger, and its gaping 
shell is clothed with a black epidermis. Along with the Mya a 
few individuals of the cockle, Cardium corbis, and of the Tellinoid 
clam, Macoma nasuta, are occasionally turned out by our uncere- 
monious spade. Here is a large round burrow, with the sides as 
smooth as if plastered. This we know to be the dwelling-place 
of one of those fossorial cray-fish of which some four or five 
species occur along the Pacific coast, and we dig on, hoping to find 
a Callianassa, a genus that we are assured is found in the bay, but 
which we have never been so fortunate as to procure there, though 
we have found it in abundance at Tomales, some fifty miles to the 
northward. Out he comes at last, a fellow about six inches long, 
with a hairy rostrum and two pincers of equal size, swimming away 
for dear life. It is only Gebia pugettensis Dana, the commonest of 
~ common species. Whether living in the mud, in the sand, among 
rs stones, it is all the same to G. pugettensis. The dredging machines 
