nautical remarks. 
653 
Juan Baptista, where it unites with the former. This arm terminates in several little 
winding creeks, leading up to the Missions of Santa Clara and San Jose. The other 
great branch takes a northerly direction, passes the Pnntas San Pablo and San Pedro, opens 
out into a spacious basin ten miles in width, and then converging to a second strait, again 
expands, and is connected with three rivers, one of which is said to take its rise in the rocky 
mountains near the source of the Columbia. 
As a general rule in San Francisco, the deepest water will be found where the tide is 
the strongest; and out of the current there is always a difficulty in landing at low water. All 
the bays, except such as are swept by the tide, have a muddy fiat, extending nearly from 
point to point, great part of which is dry at low water, and occasions the before-mentioned 
difficulty of landing ; and the north-eastern shore, from Punta San Pablo to the Rio Ca- 
lavaros beyond San Jose is so flat that light boats only can approach it at high water. 
In low tides it dries some hundred yards off" shore, and has only one fathom water at an 
average distance of one mile and a half. The northern side of the great basin beyond San 
Pablo is of the same nature. 
Alter passing the fort a ship may work up for the anchorage without apprehension, 
attending to the lead and the tides. The only hidden danger is a rock with one fathom on 
it at low water, spring tides, which lies between Alcatrasses and Yerba Buena islands. It 
has seven fathoms alongside it : the lead therefore gives no warning. The marks when on 
it are, the north end of Yerba Buena Island in one with two trees (nearly the last of the 
straggling ones) south of Palos Colorados, a wood of pines situated on the top of the hill 
over San Antonio, too conspicuous to be overlooked ; the left hand or S. E. corner of the 
Presidio just open with the first cape to the westward of it ; Sausalito Point open J- point 
with the north end of Alcatrasses; and the island of Molate in one with Punta de Sai/pedro. 
When to the eastward of Alcatrasses, and working to the S. E., or indeed to the westward, it 
is better not to stand toward this rock nearer than to bring the Table-peak in one with the 
north end of Alcatrasses Island, or to shut in Sausalito Point with the south extreme of 
it. The position of the rock may generally be known by a ripple; but this is not always 
the case. 
There are no other directions necessary in working for Yerba Buena Cove, which I 
recommend as an anchorage to all vessels intending to remain at San Francisco. 
In the navigation of the harbour much advantage may be derived from a knowledge of 
the tides. It must be remembered that there are two separate extensive branches of water 
lying nearly at right angles with each other. The ebbs from these unite in the centre of 
the bay, and occasion ripplings and eddies, and other irregularities of the stream, sometimes 
dangerous to boats. The anchorage at Yerba Buena Cove is free from these annoyances, 
and the passage up to it is nearly so after passing the Predisio. The ebb begins to make first 
from the Santa Clara arm, and runs down the south shore a full hour before the flood has 
done about Yerba Buena and Angel Island; and the flood, in its return, makes also first along 
the same shore, forcing the ebb over the Yerba Buena side, where it unites with the ebb 
from tlie north arm. 
