256 Captain Hall’s Account of the Parallel Roads 
geologists, who, as usual, differ much in opinion as to their mode 
of formation. The most natural explanation is one we suggested 
many years ago, which refers the whole of the phenomena 
to changes connected with alterations in the level of a great 
lake, that formerly occupied the district where the parallel roads 
occur. Captain Basil Hall, in his highly interesting and delight- 
ful cc Journal of a Voyage along the coasts of Chili, Peru, and 
Mexico,” employs a similar explanation in the following account 
of parallel roads or natural terraces, he met with in the Valley 
of Coquimbo *. 
“ On the 18th November, our friendly host accompanied one 
of the officers of the Conway and myself, in a ride of about 
twenty-five miles, up the valley of Coquimbo, during which, 
the most remarkable thing we saw was several series of hori- 
zontal beds, along both sides of the valley, resembling the pa- 
rallel roads of Glen Boy, in the Highlands of Scotland, so care- 
fully examined by Thomas Lauder Dick, Esq., and described 
in the ninth volume of the Edinburgh Royal Society’s Trans* 
actions. They are so disposed as to present exact counterparts 
of one another, at the same level, on opposite sides of the valley. 
They are formed entirely of loose materials, principally water- 
worn rounded stones, from the size of a nut to that of a man’s 
head. Each of these roads or levels, resembles a shingle beach, 
and there is every indication of the stones having been deposited 
at the margin of a lake, which has filled the valley up to those 
levels. These gigantic roads are at some places half a mile 
broad, but their general width is from twenty to fifty yards. 
There are three distinctly characterised sets, and a lower one, 
which is indistinct when approached, but, when viewed from a 
distance, is evidently of the same character with the others. 
The upper road lies probably 300 or 400 feet above the level 
of the sea, and 250 from the bottom of the valley ; the next 
twenty yards lower, and the next about ten yards still lower. 
These distances are loosely estimated, and may be erroneous, 
for it is difficult to determine heights or distances in a country 
quite new, and without natural and determinate objects of com- 
parison. In this valley, there being neither trees, houses, cattle, 
* There aie beautiful displays of parallel roads , in some of the valleys through 
which the Rhine flows. — E dit. 
