WOODWORTH: GEOLOGICAL EXPEDITION TO BRAZIL AND CHILE. 33 
We entered Concepcion Bay on December 8th, and on the 9th I 
went ashore at Talcahuano. I spent several days in the vicinity of 
Concepcion examining evidences of change of level. As the results 
of my observations are given in a subsequent chapter I make mention 
here only of some unrelated geological details. 
On December 11th, while yet in bed, at about ten minutes past 
seven, I felt a slight quivering followed by a sharp lurch of the hotel. 
The wooden framework of the ceiling cracked and creaked. The 
daily press stated that at 7.10 a short but violent shock was felt. 
Again on the 13th of December while in Concepcion, the daily press 
reported during various hours of the night subterranean noises ac- 
companied by a shock at 12.40 a. M., which caused some alarm. I 
was awakened at about 1.35 a. mM. by what at the time I thought was 
the fall of an object in the room below; meanwhile I heard a rumbling 
noise sounding like that made by street cars. The destruction of 
Valparaiso by the earthquake of August, 1906, has made the inhabi- 
tants fearful of a repetition of such violent earthquakes, particularly 
at Concepcion whose ancient site at Penco on the shores of the Bay 
has been the seat of the most famous earthquakes in the annals of 
Chile. The practice of the Spanish in South America of leaving a 
site more than once damaged by earthquakes has much to recommend 
it. In the case of Old Concepcion or Penco, twice destroyed by 
earthquakes and inundations from the sea, the site was mainly on a 
marsh behind a barrier beach filling out an indentation of the coastal 
hills, a location, owing to the soft nature of the recent alluvial deposits, 
likely to be severely shaken by earthquakes. The new city of Con- 
cepcion stands on a plain of Pleistocene alluvium mantling much 
disturbed sandstones which here and there rise as low hills through 
the plain. That this city has escaped destruction so far from earth- 
quakes is seemingly due rather to the failure of local violent shocks 
than to its location. 
On December 13th, I visited Penco, the site of ancient Concepcion. 
Since Darwin’s time the construction of a railway along the shore of 
the bay has led to the partial demolition of the old Spanish Fort, the 
seaward portion of the walls only remaining. (Plate 4). Of what 
I presume to be this building, Lyell states: “It has, however, been 
ascertained that the foundation of the Castle of Penco was so low in 
1835, or at so inconsiderable an elevation above the highest spring 
tides, as to discountenance the idea of any permanent upheaval in 
modern times, on the site of that ancient port; but no exact measure- 
ments or levellings appear as yet to have been made to determine this 
