“WOODWORTH: GEOLOGICAL EXPEDITION TO BRAZIL AND CHILE. 125 
-concerning the change of level accompanying the earthquake of 1835. 
As Darwin noted, little or no evidence of the elevation claimed by him 
and Fitzroy could be seen by a subsequent visitor. The Old Fort 
at Penco (Old Concepcion) is shown in Plate 4. The alleged evidence 
-of elevation prior to this famous incident pertains largely to marine 
‘shells found on the hills about the Bay of Concepcion. Another 
feature which undoubtedly is the result of relative uplift of the land 
is the alluvial plain upon which the modern city of Concepcion stands. 
* Ulloa (1772, 2, p. 252-254) who visited Concepcion Bay as early 
as 1744 describes the occurrence of shell deposits from six to twelve 
feet and more in thickness within four of five leagues from the shore 
-and also on the tops of hills fifty toises (820 feet) high. He mentions 
seeing one deposit at a height of twenty toises. 
Darwin (1887, p. 310) speaks of “the vast number of sea-shells 
scattered over the land, up to a height of certainly 600, and I believe,”’ 
he states, “of 1000 feet.”” He appears to have entertained no doubt 
that these shells were evidence of an elevation of a former sea-bottom 
to these heights as explaining the occurrence of the shells. 
The shell deposits described by Ulloa in the plain about Concepcion, 
though I did not see them, presumably are in their natural site as 
they form a part of the tilted plain of the “Formation of sand and 
shells” described by Pissis. This plain at Concepcion I estimated by 
aneroid to be forty-five feet above sea-level. Westward towards 
Talcahuano there are successive lower levels, that at the golf links 
I made seventeen feet, and the next lower level adjacent to the bay of 
Concepcion about ten feet. The surface has been more or less modified 
by the blowing of sands by the winds. I saw several boulders in the 
upper dark stratified sands of the plain between Concepcion and 
-‘Taleahuano along the railway cuts. One of these blocks was eighteen 
inches in diameter. These boulders were in an embedded position 
-and would seem to demand floating ice for their transportation. It 
is to be presumed that the water-laid portions of the deposits are 
‘therefore of Pleistocene date. 
Back of Concepcion the plain of sand abuts against the base of 
‘the Coastal Cordillera at the hill called Cerro Caracol. I searched in 
vain for any definite beach along the upper limit of the plain, but 
-stream-action would long since have obscured such local deposits at 
this juncture. Above this level to the top of Cerro Caracol the 
granitic rock displayed only evidences of long continued atmospheric 
weathering and the vertical lines of dissection worked out by running 
water. Nowhere did I observe signs of the Pleistocene stand of the 
