eight
hours, all to the northeast, one-quarter north from the Mission.
Here ends the above mentioned bay, estimated at 8 leagues. The
strait is formed by an island [i.e., Mare Island] and the
mainland of San Jose. The island soon ends and is replaced by
mainland on both sides. The strait runs to the southwest and
makes a half-turn to the south. It carries a heavy current,
depending on the rise and fall of the tide. This strait is about
two and a half leagues long and about a quarter of a league
wide, in some places somewhat wider. It ends in the land of the
Chupunes, where it becomes broader. Here we stopped at half-past
eleven o'clock at a little beach which is dry at low tide and
where the boats have to retreat 200 varas in order not to be
stranded. Here at low tide is seen a rock, which otherwise is
covered with water and which might damage the boats on landing.
However, a little farther down toward the hill is a sort of
little valley, which is good. This place we called la Division
[probably at or near Martinez]. It has a large pool of water and
plenty of firewood. Here we passed the night without incident.
The shore of the strait of the Karquines which is opposite the
mainland of San Jose is very barren.

October 17. [The party entered the delta.]

ABORIGINAL GROUPS

With the Viader and Abella diaries the formal documentary descriptions
of Costanoan people and territory east of San Francisco come to an end.
Nevertheless, there are certain other sources which convey information
of use to the ethnographer. These are, first, some of the accounts left
by travelers, particularly those by Chamisso and Choris in 1816
(translated by A. C. Mahr, 1932); second, the vocabularies and
discussion of linguistics written by Fray Felipe Arroyo de la Cuesta
(1837); third, the transcripts of the Mission baptism books made by
Pinart (no date); forth, the accumulated habitation site records of the
California Archaeological Survey. These sources will be used here for
further examination of the location of the aboriginal groups concerned
and their population.

LOCATION

The subordinate divisions of the natives inhabiting Alameda and Contra
Costa counties can probably be allocated to five primary geographical
areas. Some of these can be associated with reasonably well recognized
names; some cannot. They may be briefly considered.

_Area