WORKING GROUP 2 
ALLUM 
69 
expected of an area of rock in which the rock foliation controls the lineaments, 
with that of an area consisting of a series of dissimilar metasediments in which 
the relic bedding controls the lineaments. The two types of lineaments, in the 
writer’s opinion, are fundamentally different. 
In areas of foliated but otherwise homogeneous rock, the lineaments should 
be controlled by the foliation. Such lineaments can be expected to be numerous, 
short, and parallel to one another, and never to consist of long continuous 
ridges or valleys [Allum 1961, page 530]. 
Conversely, in areas of heterogeneous metasediments, where the lineaments 
are controlled by the bedding, they may be expected to be longer, less nume 
rous, and more evenly spaced than those controlled by foliation, and they may 
form long, continuous ridges or valleys (fig. 1) *) and possibly also show 
bedding structures [Allum 1961, page 530]. 
An outstanding paper by Ray [1960] contains, under the heading “Meta- 
morphic Rocks”, the following: “Bedding, so necessary to structural inter 
pretation, may be difficult or impossible to recognise because of physical 
changes brought about by metamorphism, including the superposition of meta- 
morphic structures of small scale. Indeed, many structural trends that can be 
interpreted from aerial photographs represent foliation rather than bedding. 
Where exposures are good, differences in photographic tone offer the best clue 
to recognition of bedding, especially where the metamorphic rocks are derived 
from thinbedded sedimentary rocks of contrasting lithologic make-up.” 
The writer’s own experience leads him to disagree with the above quotation 
and to put geomorphological expression in general, and in particular, the long, 
low, continuous, subdued, ridges so frequently found in metasedimentary 
areas, as the most reliable criterion for the recognition of the relic bedding 
strike of metasediments. Although it is true that the foliation is usually found 
to be parallel to the ridges, it is unlikely that the foliation has caused them. 
The presentation of several illustrations, in which field work confirmed that 
the ridge visible on the photographs represented bedding, would not constitute 
proof that it was always so, and it has therefore not been attempted in this 
paper. The areas actually visited in the field do not always provide the best 
photographic illustrations for the subject under discussion. Unless otherwise 
stated, therefore, the discussion of the illustrations can be assumed to have the 
general support of field work but the particular areas referred to on the illus 
trations cannot be assumed to have been visited in the field. Furthermore 
although areas of metasediments in general can be recognized as such on 
aerial photographs, it is not always possible to distinguish particular, conform 
able, meta-igneous rocks, such as sills. Therefore it is possible that a particular 
ridge or lithological horizon may not in fact be a metasediment, but the dis 
cussion, applied to the area as a whole, stands. 
The statement that the subdued ridges indicate the relic bedding rather 
9 The aerial photographs illustrating this paper are reproduced by permission of the 
British Air Ministry, British Crown Copyright reserved, and also by permission of the relevant 
countries.