8
below the volcanics, and were always to be found in
the satne stratigraphic position.
Hutton's language is complex, and his uniformi�
tarianist theories were better explained by his friend
and colleague Playfair (1802), from whom the following observations on rivers and their deposits are
culled. He suggested that the thickness of alluvial
gravels may be used to estimate the depth of erOsion
in the source area, but concluded: ' 'whether data
precise enough could be found to give weight to such
a computation must be left for future enquiry to
determine.'' Modern basin modeling techniques are
only now coming to grips with this problem, nearly
200 years later.
Fluvial facies and textural studies could be said to
have begun with Playfair's following statement:
"It is a fact very generally observed, that where the valleys
among primitive mountains open into large plains, the
gravel of those plains consists of stones, evidently derived
from the mountains. The nearer that any spot is to the
mountains, the larger are the gravel stones, and the less
rounded is their figurei and, as the distance increaSes1 this
gravel, which often forms a stratum nearly level, is covered
with a thicker bed of earth or vegetable soil ... The reason of
this gradation is evident; the farther the stones have tra�
veiled, and the more rubbing they have endured, the
smaller they grow, the more regular is the figure they
assume, and the greater quantity of that finer detritus
which constitutes the soil. The washing of the rains and
rivers is here obvious."
These observations state in a more succinct form
ideas expressed at length by Hutton (1795, Part II,
Chap. IV), although Hutton doubted that a high
degree of clast roundness could be attained except in
the sea. All these conclusions contrast strongly with
those of Finch (1823), Conybeare and Philips (1824),
Hayden (1821), and others, all of whom attributed
<'diluvial gtavelsn to the Deluge (see Schumm 1972,
p. 16), and ideas about the fluvial origin of va l leys
and alluvial deposits continued to be resisted for
many years, because they conflicted with these biblical teachings.
2.2.2 From Lyell to Davis
Charles Lyell's Principles of Geology, the first volume
of which was published in 1830, is undoubtedly
amongst the two or three most important books on
geology ever published. The intent of his book was to
establish uniformitarianism as the guiding principle
for geological interpretation, following Hutton's
teachings) and to discredit catastrophism and diluvialism. The immediate success and wide-ranging
Historical Background
influence of the book were due in large part to the
wealth of field observations that Lyell was able to
bring to bear on his thesis1 based on his travels
throughout Britain, France, and Italy. Von Hoff
(1822-1824) had published a treatise earlier on the
theme <'investigation of the changes that have taken
place in the earth's surface conformation since his�
toric times1 and the application which can be made
of such knowledge in investigating revolut i ons beyond the domain of history". This work provided
copious documentation of recent geological activity
around the shores of the Mediterranean Sea and the
Black Sea, such as alluvial deposition and changes in
sea level, but the work was based mainly on literature
research1 Von Hoff not having the means for travel
available to Lyell, and his treatise did not receive the
recognition it deserved (Zittel 1901, p. 188). Lyell
acknowledged that much of the information that he
used in his Principles came from Von Hoff, «but he
helped me not to my scientific view of causes )) (letter
quoted in Bailey 1962, p. 78; Wilson 1972, p' 276).
Among his more important pieces of fieldwork,
Lyell observed Tertiary fluvial deposits interbedded
with lacustrine sediments and lava flows in the
Auvergne, France, and Tertiary fluvial g- ravels containing beds of day with marine fossils near Nice
(Wilson 1972, Chap. 7). These clearly demonstrated
to Lyell the long and complex geological histories of
these regions, explainable in terms of processes acting at the present day over long periods of time, but
quite incompatible with catastrophist hypotheses.
Five chapters in the first volume of the Principles
(1st edition) are devoted to rivers and deltas. Lyell
described the way in which river meanders gradually
enlarge themselves and develop neck cutoffs by
wearing away at their banks (Fig. 2.2):
"When the tortuous fl exures of a river are extremely great,
the aberration from the direct line of descent is often
restored by the river cutting through the isthmus which
separates two neighboring curves."
Lyell thought that meanders were initiated as deflections caused by the walls of the valley or by
variations in the thickness or hardness of the alluvial
valley deposits. He quoted earl i er work of Flint on
the Mississippi River to the effect that opposite each
Fig. 2.2. A river meander, showing a potential neck cutoff
(a). (From Lye!l l830)
below the volcanics, and were always to be found in
the satne stratigraphic position.
Hutton's language is complex, and his uniformi�
tarianist theories were better explained by his friend
and colleague Playfair (1802), from whom the following observations on rivers and their deposits are
culled. He suggested that the thickness of alluvial
gravels may be used to estimate the depth of erOsion
in the source area, but concluded: ' 'whether data
precise enough could be found to give weight to such
a computation must be left for future enquiry to
determine.'' Modern basin modeling techniques are
only now coming to grips with this problem, nearly
200 years later.
Fluvial facies and textural studies could be said to
have begun with Playfair's following statement:
"It is a fact very generally observed, that where the valleys
among primitive mountains open into large plains, the
gravel of those plains consists of stones, evidently derived
from the mountains. The nearer that any spot is to the
mountains, the larger are the gravel stones, and the less
rounded is their figurei and, as the distance increaSes1 this
gravel, which often forms a stratum nearly level, is covered
with a thicker bed of earth or vegetable soil ... The reason of
this gradation is evident; the farther the stones have tra�
veiled, and the more rubbing they have endured, the
smaller they grow, the more regular is the figure they
assume, and the greater quantity of that finer detritus
which constitutes the soil. The washing of the rains and
rivers is here obvious."
These observations state in a more succinct form
ideas expressed at length by Hutton (1795, Part II,
Chap. IV), although Hutton doubted that a high
degree of clast roundness could be attained except in
the sea. All these conclusions contrast strongly with
those of Finch (1823), Conybeare and Philips (1824),
Hayden (1821), and others, all of whom attributed
<'diluvial gtavelsn to the Deluge (see Schumm 1972,
p. 16), and ideas about the fluvial origin of va l leys
and alluvial deposits continued to be resisted for
many years, because they conflicted with these biblical teachings.
2.2.2 From Lyell to Davis
Charles Lyell's Principles of Geology, the first volume
of which was published in 1830, is undoubtedly
amongst the two or three most important books on
geology ever published. The intent of his book was to
establish uniformitarianism as the guiding principle
for geological interpretation, following Hutton's
teachings) and to discredit catastrophism and diluvialism. The immediate success and wide-ranging
Historical Background
influence of the book were due in large part to the
wealth of field observations that Lyell was able to
bring to bear on his thesis1 based on his travels
throughout Britain, France, and Italy. Von Hoff
(1822-1824) had published a treatise earlier on the
theme <'investigation of the changes that have taken
place in the earth's surface conformation since his�
toric times1 and the application which can be made
of such knowledge in investigating revolut i ons beyond the domain of history". This work provided
copious documentation of recent geological activity
around the shores of the Mediterranean Sea and the
Black Sea, such as alluvial deposition and changes in
sea level, but the work was based mainly on literature
research1 Von Hoff not having the means for travel
available to Lyell, and his treatise did not receive the
recognition it deserved (Zittel 1901, p. 188). Lyell
acknowledged that much of the information that he
used in his Principles came from Von Hoff, «but he
helped me not to my scientific view of causes )) (letter
quoted in Bailey 1962, p. 78; Wilson 1972, p' 276).
Among his more important pieces of fieldwork,
Lyell observed Tertiary fluvial deposits interbedded
with lacustrine sediments and lava flows in the
Auvergne, France, and Tertiary fluvial g- ravels containing beds of day with marine fossils near Nice
(Wilson 1972, Chap. 7). These clearly demonstrated
to Lyell the long and complex geological histories of
these regions, explainable in terms of processes acting at the present day over long periods of time, but
quite incompatible with catastrophist hypotheses.
Five chapters in the first volume of the Principles
(1st edition) are devoted to rivers and deltas. Lyell
described the way in which river meanders gradually
enlarge themselves and develop neck cutoffs by
wearing away at their banks (Fig. 2.2):
"When the tortuous fl exures of a river are extremely great,
the aberration from the direct line of descent is often
restored by the river cutting through the isthmus which
separates two neighboring curves."
Lyell thought that meanders were initiated as deflections caused by the walls of the valley or by
variations in the thickness or hardness of the alluvial
valley deposits. He quoted earl i er work of Flint on
the Mississippi River to the effect that opposite each
Fig. 2.2. A river meander, showing a potential neck cutoff
(a). (From Lye!l l830)