510 SALTILLO 
each bearing on his or her arma serape for sale; and 
I doubt whether, since the occupation of the country 
by the Americans, they have found so good a market 
for their productions. Many gentlemen of the party 
had been desirous to take home with them one of these 
articles; and the opportunity now presented of buy-» 
ing them fresh from the loom, and at prices much 
lower than we had seen them in the shops of Monterey 
and Saltillo, induced many to secure specimens. 
In walking round the camp, my attention was at- 
tracted to some large oyster shells, which protruded 
above the clay bank; and, on extending my examina- 
tion about seventy yards to the south, to a deep arroyo, 
I noticed thick beds of shells of the genus Ostrea, in 
its sides and on its bottom. According to Dr. Til- 
den. these beds extend up to near Loredo; and Dr. 
Wislizenus found them two miles below Mier on the 
immediate banks of the river. Our camp was near 
the town, and the surface of the clay bank where we 
found them, was at least fifty feet above the river. 
We now set out for Camargo, twenty-five miles dis- 
tant, keeping the western bank of the river, through a 
forest of chapporal. About several miles distant on 
the opposite bank, we saw the town of Roma, and soon 
after were cheered with the sight of a small steamboat, 
which occasionally works its way as far as this. It is 
evident that the navigation is attended with difficulties, 
as we saw her more than once fast on sandbars, which 
here begin to obstruct the navigation. 
Finding that the train would not reach Camargo 
before dark, and being anxious to get to Ringgold 
Barracks as soon as possible, I set off in advance, ac- 
