,,the ,,principles ,,and ,,objects ,,of 
,,geology4                              
,,ministry ,,of ,,finance1 ,,egypt4     
99 99 99 99 99                          
,,survey ,,department4                  
99 99 99 99 99                          
,,the                     ,,principles  
,,and ,,objects ,,of ,,geology          
,,with ,,special ,,reference ,,to       
,,the ,,geology ,,of ,,egypt1           
,,by                     ,w4 ,f4 ,,hume1
 ,d4,,sc41 ,f4,r4,s4,e41 ,,etc4         
,,director1 ,,geological ,,survey ,,of  
,,egypt4                                
99 99 99 99 99         ,technical       
,lectures delivered in the ,survey      
,department1 ,giza1                  on 
,january #bj1 and ,february #aj1 #aiaj4 
,decoration                             
,,cairo3               ,printed at the  
,,national ,,printing ,,department1     
and to be obtained at the ,,sale-,,room1
 ,geological ,museum1 ,ministry of      
,public ,works ,gardens2 at the ,,survey
 ,,department1 ,giza 7,mudiria72 or     

through any ,bookseller                 
99 99 99 99 99                          
#aiaa4    ,,price #e ,p4,t4             
,,illustrations4                        
99 99 99 99 99                          
,,page4      ,fig4 #a4 -- ,two          
,anticlines and a ,syncline             
#f          #b4 -- ,overfolding of      
,strata                                 
#g          #c4 -- ,unconformity        
exhibited in the ,faym                  
#h          #d4 -- ,fault exhibited by a
 ,coal-seam                           #h
          #e4 -- ,sand-erosion of       
,sandstone ,cliff at              ,gebel
 el ,tunb                               
,facing       #aj          #f4 --       
,water-worn ,amphitheatre in            
,side-valley              of ,um        
,leseifa                                
#aj          #g4 -- ,denudation ,effects
 in a ,district of                      
,sedimentary ,rocks                     
#aa          #h4 -- ,denudation ,effects
 in a ,district of              ,igneous

 ,rocks                                 
#aa                                   99
 99 99 99 99                            
,,the ,,principles ,,and ,,objects ,,of 
,,geology                         ,,with
 ,,special ,,reference ,,to             
,,the ,,geology ,,of ,,egypt4           
99 99 99 99 99                          
,i4--,,general4      ,the systematic    
examination of the geological structure 
of ,egypt1  carried out by the          
,geological ,survey during the last     
thirteen years1  has1 in conjunction    
with previous studies1 revealed the fact
 that  the surface of the country is    
composed of very varied materials3      
limestones1 sands1 clays1 sandstones1   
granites1 schists1 etc4 ,the            
co-ordination of view as to the         
distribution of these rocks#a  presented
 by a geological map has further shown  
that they are not  arranged in a random 
manner1 but that certain very definite  
relations  exist between them4 ,if1 for 
instance1 the ,moqattam hills behind    

the ,citadel be ascended1 the lower part
 of the scarp is found to be  composed  
of white limestone1 which is capped by a
 series of sandy  limestones and clays  
differing alike in colour and in the    
rapidity  with which they are worn away 
by the streams1 due to the rare but     
destructive winter rains4 ,finally1 the 
summit is crowned by beds  in which     
boulders of flint and quartz play the   
most important part1  the matrix of sand
 which bound them together having long  
been removed  by the action of the wind4
    ,similarly1 if we were to go        
southward towards ,aswan1 a change would
  be noted in the character and         
composition of the rocks which form  the
 cliffs bordering the ,nile ,valley4    
,from ,cairo to ,qena1 limestones       
predominate2 but from thence southward  
to ,esna1 clays play a large  part at   
the base of the limestones1 and the     
slipping of the latter  over these      
softer members has given rise to the    
8tumbled0 country  which is so          

conspicuous a feature between ,armant   
and ,matana4 ,south of  ,esna the clays 
in their turn disappear1 while the      
sandstone which is  seen underlying them
 near ,mahamid becomes the dominant     
constituent  of the hills from near     
,edfu to the neighbourhood of ,aswan2 at
 this  locality the sandstone itself    
vanishes1 except in so far as it forms  
isolated caps on the granite1 which is  
the principal rock in the  well-known   
district of the ,first ,cataract4       
,the same lesson as to the order of     
succession of the rocks in ,egypt  is   
forced home if we move from ,qena       
eastward to the ,red ,sea hills1  or    
south-westward to ,kharga ,oasis4 ,east 
of ,qena the clays are a  conspicuous   
feature at the base of the outlying     
limestone hills 7,abu  ,had1 etc471 and 
in their turn rest on sandstone1 which  
forms striking  plateaus seamed by deep 
ravines giving entry to the heart of the
 ,red  ,sea hills4 ,on traversing these 
gorges1 a confused hill-country of      

granite 7worn into boulders on the      
surface71 or dark-green schists is      
entered1 on whose summits the sandstone 
occurs as isolated outliers  near the   
main sandstone mass1 but to the east    
disappears altogether4    ,similarly1   
going westward and crossing the great   
limestone desert1 on  reaching the edge 
of the scarp which bounds the oases1    
clays appear  from under the limestones1
 and in their turn overlie sandstones   
forming the floors of the oasis         
depressions4 ,closer examination        
reveals the fact that in the upper part 
of the sandstone series seams  of clay  
alternate with the sandy layers1 and in 
that part of the cliff  where clay bands
 predominate1 beds of limestone         
alternate with them4    ,in broad       
outline1 it may be stated that in       
southern ,egypt1 limestone  rests on    
clays alternating with limestone1 these 
on sandstones which  in their upper part
 alternate with clay1 and the sandstone 
on granite  and metamorphic rocks       

7slates1 schists1 etc474 ,the           
inclination or dip  of the various beds 
is such that should a boring be made    
through the  limestone near ,cairo1 one 
might expect to reach first a succession
  of beds where clay was predominant1   
followed by beds of sandstone1  and     
finally the series of which the granite 
of ,aswan is a conspicuous  member4#b   
,in northern ,egypt1 the conditions are 
reversed1 sandstones  and clays         
overlying the limestones near ,cairo1   
but never attaining  the extent and     
importance of those exposed to view in  
the south4    ,these facts require an   
explanation--the one furnished by the   
science  of ,geology1 being briefly as  
follows3 ,each of the rocks observed    
has a definite origin or formation2 the 
nature of their present  distribution is
 due to subsequent movement1 or         
deformation2 the  various meteorological
 agencies at work lead to the           
transformation of  the original         
structures1 resulting in the formation  

of a new series  of rocks composed of   
materials derived from the wearing away 
of the  older deposits4                 
,,ii4--,,origin ,,or ,,formation ,,of   
,,rocks4      ,the simplest illustration
 of the formation of a rock is one which
  may be observed by the dweller in     
,egypt every year during the ,nile      
flood4 ,the 8red water0 of the ,nile1 if
 collected during this  period1 and     
evaporated to dryness1 leaves behind it 
the fine-grained  sediment1 or ,nile    
mud1 forming the soil to which this land
 owes its  fertility2 while in the      
central portions of the river1 the      
coarser  material1 consisting largely of
 sand-grains1 is being transported by   
the stronger current4 ,as a result1 the 
river flows for the main part  over a   
sandy bed1 the clays being restricted to
 the sides where the  water is moving   
less swiftly1 or to the fields on which 
the finer  sediment is deposited4 ,this 
8red water0 has been traced step by     
step to its parent source1 and has been 

proved to be derived from  the wearing  
away of the widely-spread volcanic rocks
 of ,abyssinia1  disintegrated by       
differences of temperature1 etc41 and   
denuded  by the destructive rainstorms  
which break over that region in the     
early summer4 ,it is equally a matter of
 experience that on drying1  this       
sediment passes from the condition of a 
soft and sticky mud  to a hard and      
resistant clay1 which1 drying during the
 heat of the  summer1 cracks in every   
direction4 ,the fluviatile character of 
these  clay deposits is often revealed  
by the presence of the river shells     
enclosed in them1 and in each succeeding
 year slight differences  in composition
 in the material brought down are       
indicated by the  layers being sharply  
marked off from one another1 and so     
presenting  the familiar stratified     
appearance4 ,again1 much sand and clay  
is  being carried seaward and deposited1
 the former1 in general1 nearer  the    
land on account of its greater specific 

gravity and less finely  divided        
character4    ,these clays and sands are
 forming both on the land and in the    
sea1  a point which does not need       
elaboration1 but when considering the   
origin of the limestones1 and how it is 
that they seem at times to  be built up 
of fossil shells1 as a rule the general 
student would  be at a loss for an      
answer4 ,the researches in the great    
oceans1  which have been carried on with
 such assiduity during recent years1    
have shown that the upper layers of     
their waters are crowded with a  vast   
number of living organisms1 apparently  
simple in structure1 but  having the    
power of extracting the carbonate of    
lime in solution and  constructing      
shells of complicated and beautiful     
form4 ,as the animals  die1 these tiny  
shells rain down to the bed of the      
ocean1 slowly  forming a muddy white    
calcareous paste which encloses the     
sea-urchins  and other marine animals   
living in the depths of the sea4 ,thus1 

step  by step1 muds 7which on drying are
 as genuine limestones as any now       
forming the cliffs and scarps of ,egypt7
 are laid down on one another1          
separated into strata whenever some     
external change1 such as the  addition  
of some clayey matter transported from a
 river in flood1  slightly alters the   
composition4 ,the alteration is         
subsequently  indicated either by       
variation in tint or by differing       
resistance  to the wearing influences of
 the meteorological agencies4 ,but how  
are these argillaceous muds transformed 
into the solid clays1 the  sands into   
sandstones1 and the calcareous muds into
 fossiliferous  limestones8 ,how have   
these loose materials become            
consolidated so  as to form the compact 
rock-masses with which we become        
acquainted  in the most casual study of 
the physical structure of ,egypt8       
,,iii4--,,deformation ,,of ,,rocks4     
,examination of the rock exposures at   
many localities in the  neighbourhood of

 ,cairo bears witness to the fact that  
the strata of  limestone which were laid
 down horizontally upon the bed of the  
sea  are no longer in the position they 
once occupied1 but are now inclined  to 
the horizontal plane at angles which are
 easily perceptible4 ,this  is          
especially noticeable in the two shallow
 cuttings under the  ,great ,pyramid1   
where the strata are inclined #e degrees
 to the  south1 revealing the reason why
 the whole ,pyramid slope descends so   
rapidly in the southward direction4     
,again1 if standing at the base  of the 
same mighty structure1 the gaze be      
allowed to wander over  the broad       
expanse of the ,nile ,valley to the     
scarp of the ,moqattam  hills behind the
 ,citadel1 it will be seen that the     
white limestone  of their lower slopes  
forms1 not a long horizontal wall1 but  
an arch1  sloping strongly both north   
and south of the ,citadel4 ,there has   
been  obviously change of form1 but how 
has it taken place8    ,we learn with   

surprise that an earthquake shock in    
distant ,san  ,francisco or in the      
inhospitable regions of ,turkestan has  
recorded  itself through the            
delicately-poised recorder at ,helwan1  
long before  the dire news of           
destruction has flashed along the       
telegraph wire  to the same destination4
 ,there is a realization of the         
instability  of the earth's crust1 in   
spite of the solidarity of its component
  parts1 but though the sudden shocks   
bring home this truth1 it is  not so    
readily grasped that day by day and hour
 by hour parts of the  earth's crust are
 slowly rising and others sinking1      
offering stern  problems to the dwellers
 on the shores where these changes are  
most  markedly taking place4 ,on the    
eastern shores of ,england1 towns and   
forests are being submerged beneath the 
relentless advance of the sea2  on the  
coasts of the ,scandinavian peninsula1  
etc41 on the other hand1  beaches       
formerly beneath the sea now stand high 

above the influence of  its waves1 and  
in ,egypt coral-reefs which once grew   
beneath the waters  of the ,red ,sea    
rise in places to over two hundred      
metres above it in  bold hills or       
steep-sided terraces4 ,though possibly  
of far greater  importance and          
significance than the sudden convulsions
 which have  left so deep an impression 
on the mind of man1 these movements are 
nevertheless so imperceptible that they 
arouse little attention4    ,a second   
type of deformation is noted where heavy
 masses of one  rock rest on other and  
softer materials4 ,the underlying beds  
are  then often compressed and          
contorted2 clays1 for instance1 are     
drawn out into thinner lamin1 giving    
rise to shales1 while the  massive rocks
 above either slip on the surface of the
 lower ones1  if these be impermeable1  
and so permit of a water-layer forming  
along the junction1 or else descend by  
sheer weight1 producing a  confused area
 of mixed materials in front of the     

still unshattered  cliffs4 ,examples of 
this nature abound in ,egypt wherever   
the ,eocene  limestones rest on the     
,cretaceous clays2 on the railway from  
,armant  to ,matana the resulting       
effects are well observed near ,shagab4 
,here  in the main cliff the massive    
limestones are seen resting on the  soft
 bluish clays1 while in front is a      
wilderness of low hills in  which       
limestones and clays are mixed1 broken  
and contorted4 ,but while  these        
deformations may be irregular and local1
 there remain greater  pressure-effects 
which have been regional in character1  
and by whose  agency the solid rocks    
have been folded in the most remarkable 
manner1  strata once horizontal being   
thrown into arches1 or anticlines1  and 
basin-like curves1 or synclines4 ,the   
importance of these changes  cannot be  
over-estimated1 and some of the marked  
features of ,egyptian  scenery depend   
directly on these effects4 ,reference   
has already been  made to the slope of  

the ,pyramid plateau1 but the character 
of ,egypt  in far broader outline       
depends on the results of these         
pressures and  the foldings so produced4
 ,a glance at the map suffices to show  
that  many of the salient features in   
this country present a remarkable       
similarity and parallelism4 ,the eastern
 cliff-wall of ,kharga ,oasis  preserves
 a notable parallelism to a portion of  
the ,nile ,valley1  though the latter be
 separated by many kilometres of wild   
desert  plateau from the oasis2 another 
portion of the ,nile ,valley also       
agrees with the ,gulf of ,suez in the   
broad outlines of its trend4            
,illustration3 ,fig4 #a4--,two          
,anticlines and a ,syncline4#c    ,a    
section taken from ,baharia or ,kharga  
,oasis to the shores of the  ,red ,sea  
reveals the fact that ,egypt proper is  
bounded on the west  by a low flat arch 
which has brought the underlying        
sandstones  nearer to the surface1      
giving rise to the great oases4#d ,these

  are mainly present in the sandstone   
areas1 and are in part bounded  by      
cliff-walls composed in many instances  
of clays at the base and  limestones at 
the summit4 ,to the east1 on the other  
hand1 rise the  ,red ,sea hills1 the    
central core of a steeply inclined arch 
in which  the resistant granites and    
schists now rise high above the         
low-lying  sandstone country which      
flanks them4 ,between these two arches  
is  the flat-bedded syncline in which   
the nummulitic limestone is the         
conspicuous member1 the strata in       
central ,egypt having in consequence  a 
half cup-shaped form1 of which one half1
 the northern1 may have  disappeared by 
fracture beneath the waters of the      
,mediterranean  ,sea4 ,this cup-like    
structure may be due to ,egypt having   
not only  been folded in a north-west   
and south-east direction but also almost
  at right angles1 this latter folding  
giving rise to such remarkable  features
 as the ,wadi ,araba1 the ,qena bend1   

and possibly affording the  fundamental 
explanation for the great ,s-shaped     
bends of the ,nile4 ,in  other and more 
mountainous regions1 such as the ,alps  
and ,himalayas1  these solid earth-waves
 may be under such immense pressure that
 their  crests begin first to turn over 
like those of an advancing wave of  the 
sea1 and then may be broken in such a   
way that mighty masses  of strata are   
rent asunder1 those portions which are  
uppermost  being thrust for great       
distances over the underlying beds4     
,these  extreme folds ending in         
fracture1 or overthrusts1 are as yet but
  little known in ,egypt1 though ,dr4   
,ball has reported an interesting  case 
from the neighbourhood of ,abu ,harba1  
and some of the phenomena  of           
dislocation observed near the borders of
 the ,gulf of ,suez may  possibly be    
explained as resulting from movements of
 this nature4    ,illustration3 ,fig4   
#b4--,overfolding of ,strata4    ,these 
intense movements become masked under   

the influence of the  denuding hand of  
time1 the contorted strata may again    
sink beneath the  sea1 new beds are laid
 down horizontally on the upturned edges
 of the  older series and the result is 
the production of an unconformity       
between the two members1 which differ in
 age1 in inclination1  and in fossil    
character4 ,sometimes rolled fragments  
of the older  stratum are interposed    
between it and the new overlying beds1  
further  revealing the activity of      
denudation before the newer member began
  to be deposited4    ,if fracture by   
overthrust be unknown in ,egypt1 another
 type of  fracture has produced effects 
of a far-reaching character4 ,in certain
  regions of the earth1 folding is no   
longer the conspicuous method  by which 
the rock-components of its crust are    
displaced with regard  to one another4  
,in many instances small fissures have  
been observed  in which the beds on one 
side have been thrown down to a lower   
level  than they are on the other4      

,these faults are frequently the result 
of  great earthquakes1 many striking    
examples of such occurrences having     
been noted during the major             
earth-movements within the last hundred 
years4 ,it is probable1 indeed1 that    
many of the most important of  these1   
such as the destructive earthquake of   
,messina1 are due to  further settling  
of the strata in relation to            
fracture-lines already  determined4     
,naturally1 this implies that there are 
certain spaces  formed deep beneath the 
earth's surface1 which permit of these  
efforts to restrengthen the weak spots  
by filling up the gaps4 ,in the  extreme
 outskirts of ,egypt these fault-lines  
have produced marvellous  and striking  
effects1 the most conspicuous being the 
remarkable  depression which1 commencing
 at the ,gulf of ,aqaba1 penetrates far 
into the continent of ,asia1 giving rise
 to the ,dead ,sea 7many hundred  metres
 below the level of the ,mediterranean71
 to the ,jordan ,valley1  to the ,lake  

of ,tiberias1 and the valley which      
continues this line  northward4 ,i have 
had the opportunity of personally       
studying some  of these fault-lines in  
the ,sinai peninsula1 tracing them from 
an  arched fold in the north1 whose     
sides were being let down by faults  in 
a series of steps1 to a trough-fault1 in
 which the younger strata  are displaced
 bodily between the older ones4 ,where  
undisturbed1 the  succession in ,sinai  
shows sandstone lying on granite1 and   
limestone  7containing definite groups  
of fossils7 on sandstone4 ,in the       
valleys  due to these trough-faults1 the
 granite hills tower #ejj metres on each
  side1 capped by small outlying        
fragments of the overlying sandstone1   
whereas in the valley itself the only   
rocks visible are limestones  and       
sandstones often tilted at high angles1 
and thus revealing the  tremendous      
displacement to which they have been    
subjected4    ,illustration3 ,fig4      
#c4--,unconformity exhibited in the     

,faym4    ,illustration3 ,fig           
#d4--;,fault exhibited by a ,coal-seam4 
,considering the earth-movements of     
,egypt as a whole1 the evidence  shows  
folding to have been the more important 
type of displacement on  its western    
side1 and intense faulting to have been 
most conspicuous  in the east1 while    
between these two extremes1 the relative
 importance  of folding and faulting    
will remain a contested point4 ,the     
discussion  will only close when the    
borders of the ,nile ,valley and the    
,gulf  of ,suez have been mapped with   
the accuracy and precision of a         
,geological ,survey in ,europe--a pious 
aspiration1 whose realization  can      
scarcely be hoped for while the broad   
geological picture is  still being      
filled in4    ,egypt1 then1 has passed  
through a long history1 of which the    
following seems to be the record put in 
dogmatic form4 ,the ancient  schists and
 granites which form the central core of
 its eastern  arch1 or anticline1 the   

,red ,sea hills1 are witnesses to a     
period  of sedimentation1 of volcanic   
action1 and of the influence of         
deep-seated molten igneous masses4 ,step
 by step these were revealed  by        
denudation1 becoming part of an ancient 
continent4 ,in addition to  a brief     
marine invasion during the              
,carboniferous period1 there was a      
second advance of the sea in ,cretaceous
 times1 which is represented  first by  
the deposit of such coarse detrital     
materials as the sands  composing the   
,nubian sandstones4 ,then1 as the       
depression increased1  only the finer   
clayey materials reached the ,egyptian  
region1 and  finally the sea covered1 if
 not the whole1 at least the greater    
part of its area for a lengthened       
period4 ,with the close of the  ,eocene 
epoch a reverse movement set in1 by     
which the pure white  marine limestones 
of the ,moqattam hills were capped by   
the sandy  limestones and clays forming 
the brown-tinted beds of their upper    

portion1 the whole being1 in its turn1  
covered by the coarse flint  and quartz 
gravel which containing silicified      
trees#e is the chief  desert-former in  
the immediate neighbourhood of ,cairo1  
as also of  a large area in north-west  
,egypt4 ,any gain by the sea since this 
period has been comparatively local and 
limited1 and the present  conditions    
suggest that the land is gaining on the 
sea rather than  the reverse4 ,the great
 fold-movements which we have seen to   
determine  so many important features   
are relatively of very late date in this
  series of events1 on their nature and 
position depending the present          
character and visible extent of the     
different formations4                   
,,iv4--,,physical ,,transformation ,,of 
,,rocks4      ,the geological features  
of ,egypt as presented to-day are the   
results  of the formation through       
varying conditions and the subsequent   
deformation of the rocks composing its  
solid crust2 we may next  consider the  

varied agencies through whose action    
these are now  undergoing               
transformation4 ,a comparatively small  
portion of this  country is undergoing  
erosion by the sea1 and if elevation be 
still  taking place1 there is rather    
gain from the sea than destruction  by  
it4    ,very different1 however1 are the
 meteorological agencies which are  at  
work fashioning the land as a whole1 the
 effects of wind-blown  sand1 rain1 and 
river being of prime importance4        
,different in these  respects are the   
,eastern and ,western ,deserts of       
,egypt4 ,if the western  border of the  
river be examined in ,southern ,egypt1  
and especially in  ,nubia1 the sight of 
huge masses of golden-tinted sand       
filling every  wind-sheltered hollow    
might well leave the impression that the
 vast  desert plain behind was covered  
by a pall of sand4 ,closer study  has   
shown that these wind-swept expanses    
afford no protection or  resting-place  
for the finer sands and that            

consequently their floor  must be formed
 of the more solid materials which wind 
cannot carry  before it4 ,if this be    
realized1 no astonishment will be felt  
that  the ,libyan ,desert surface is    
composed of limestone1 or of coarse     
gravels from between whose larger       
fragments all the finer sand has  been  
swept away4    ,illustration3 ,fig4     
#e4--,sand-erosion of ,sandstone ,cliff 
at ,gebel  el ,tunb4 ,wadi ,qena1       
,eastern ,desert4    ,illustration3     
,fig4 #f4--;,amphitheatre in            
,side-valley of ,um ,leseifa1           
north-east of ,qena1 due to erosion of  
,limestone by the action of  ,temporary 
,torrents4                              
,facing p4 #aj4    ,however1 the        
wind-borne sand leaves its mark on the  
limestones1  which in some places are   
seamed by delicate grooves parallel to  
the sand-blast1 and in others1 where    
they are softer1 have been  sculptured  
into low hummocks often scattered over  
immense tracts  of country4 ,the sand   

itself has a strangely local            
distribution1  advancing across the     
desert in lines of enormous length1 and 
usually  trending in an almost          
meridional direction4 ,the supply does  
not come  from the south or south-west1 
as might at first sight be expected1    
but from the north1 and most of the     
great dune-systems1 which occur  around 
and beyond the great oases1 have their  
termination in the  southern direction4 
,even the series of dunes1 over #ajj    
metres high1  which prevented the       
,rohlfs party advancing westward from   
,dakhla to  ,kufra1 come to an end      
further to the south1 leaving the wide  
sandstone  plains bare4#f ,in the oasis 
of ,kharga the dominant longitudinal    
type  is replaced by huge crescentic    
dunes which1 separated by broad spaces  
clear of sand1 follow one another along 
a north-south line1 and are  not stopped
 in their onward march even by ridges of
 considerable  size4 ,the reasons have  
still to be found for these lines of    

special  sand aggregation1 though when  
studying the cataract district of       
,amara1  the initial formation of a     
dune-system was seen to be determined by
  a local depression1 which had given   
sufficient protection for the  formation
 of a sandy base on which the dune could
 then be built up4    ,illustration3    
,denudation ,effects in a ,district of  
,sedimentary ,rocks4    ,fig4 #g4--,um  
,leseifa camp 7looking west74 ,the      
harder beds of limestone  form          
precipitous ledges4    ,illustration3   
,denudation ,effects in a ,district of  
,igneous ,rocks4    ,fig4 #h4--,view of 
,diorite ,hills near ,gebel ,sobeir1    
,eastern ,desert  of ,egypt4            
,facing p4 #aa4    ,not only are        
limestones grooved and seamed1 but      
certain areas of  the ,western ,desert  
are covered with curious melon-shaped   
masses1  harder concretionary portions  
remaining after the softer materials  of
 the beds have been carried away by     
wind-action1 whereas in the  region to  

the east of the ,nile these concretions 
are still enclosed  in the softer       
limestones4    ,still more striking is  
the effect of the wind-blown sand in the
  sandstone and granitic regions4 ,here 
the complex composition of  the granite 
has made it a ready victim4 ,the softer 
felspars and mica  having been worn by  
the impact1 leave the quartz grains     
loose upon the  surface1 and give the   
rock a 8frittered0 appearance4 ,holes   
have  been formed in the windward side  
of the blocks1 and the sand contained   
in them clearly shows the agency to     
which they owe their origin4    ,near   
the eastern edge of the ,western ,desert
 the effects of  water-action become    
more conspicuous1 on the borders of the 
,faym  terrace-formation being a marked 
feature1 and there is a transition  to  
the dominant characteristics which mark 
the limestone country  eastward of the  
,nile4 ,here1 deep and intricate        
valley-systems have  been cut out from a
 plateau which a few kilometres from the

 ,nile  is as flat as the great western 
plains4 ,one of the best known  examples
 is the ,wadi ,hof1 near ,helwan1 with  
its ramifications1  terminating in steep
 cliff-faces having all the appearances 
of 8dry  waterfalls40 ,any doubt as to  
the active agent in their production  is
 set at rest by an examination of the   
excellent photographs taken  by various 
observers during the great storms which 
almost annually  burst over this region4
 7,the lecture was illustrated by a     
series of  slides showing ,wadi ,hof in 
flood1 and the cascades descending the  
8waterfalls0 which terminate its        
side-channels1 these being most  kindly 
lent to the writer by ,herr ,zst1 of the
 ,electrical ,service1  ,ministry of    
,public ,works74 ,the great annual and  
diurnal temperature  variations 7over   
#ej ,c47 aid in the work of denudation  
by preparing  an immense amount of      
broken material through the contraction 
and  expansion which they produce4 ,as  
every material expands and contracts    

according as it is heated or cooled1 so 
the different component  parts of the   
rocks composing the earth's crust are in
 constant  movement with regard to one  
another1 and the less homogeneous they  
are the greater the effect in breaking  
them up into small masses or  particles4
 ,these loosened fragments which cover  
the surface of the  desert are thus     
ready to be swept away by the           
rain-waters1 and as we  have already    
seen1 it is owing to these effects1     
superadded to more  subtle changes next 
to be considered1 that the old volcanic 
rocks  of ,abyssinia yield the rich silt
 or mud of the ,nile ,valley4 ,it would 
be difficult to estimate the rapidity   
with which these wild ravines  are being
 deepened by any comparison with        
water-wearing effects in  ,europe4 ,any 
beds of soft sands and clays are rapidly
 dissected by  the torrent waters1 a    
feature which readily explains the      
absence  of conspicuous hills in the    
,eastern ,desert east of ,esna1 where   

the  ,cretaceous clays form the dominant
 constituent in the geological          
structure of the country4 ,whatever the 
effects of sand-erosion in the  ,western
 ,desert or rain-erosion in the hills   
and on the plateaus of  the ,eastern    
,desert of ,egypt1 they come relatively 
but little under  the notice of the     
dweller on the ,nile1 to whom the       
river-erosion  and the reformation of   
new materials become of primary         
importance4    ,even the powerful agency
 of frost cannot be entirely dismissed  
from  consideration in ,egypt4 ,owing to
 the expansion of water when converted  
into ice1 the rocks in whose cracks the 
water has collected are split  asunder1 
and as we have recently noted1          
temperatures lower than #b  ,c4 have    
been recorded in ,cairo during the      
present winter 7#aiaj74 ,on  the great  
desert plateau which extends from       
,kharga ,oasis to the ,nile  ,valley1   
temperatures of #bd ,f4 and #cj ,f4 were
 also observed1 and  in the ,red ,sea   

hills and ,sinai frost must be of common
 occurrence1  as one mountain in the    
latter peninsula was ascended in snow1  
and  the higher peaks are frequently    
covered in a white pall4    ,the nature 
of a river system need not be dealt with
 in much detail  here1 as ,i have       
already discussed this subject in       
8,survey ,notes0  for ,april1 #aijg1    
under the title of 8,river              
,characteristics as  illustrated by the 
,nile40 ,it may be well1 however1 to    
recall that a  normal river passes      
through three distinct phases of        
activity4 ,in its  mountain tract 7for  
most large rivers arise in the higher   
altitudes7  there is maximum erosion and
 backward growth of the river system4   
,in  its central portion1 or valley     
tract1 the stream is acting as a        
transporter of eroded material1 and such
 erosion as there is1 is  downward      
rather than sideward4 ,finally1 the     
plain tract is the region  of deposition
 of the materials so carried1 erosion   

being lateral1  and the growth of the   
stream bed forward in the form of a     
fan-shaped  delta where the transported 
sands and clays enter the sea4    ,but  
this general succession may be further  
complicated by  circumstances depending 
upon the geological conditions4 ,in     
,egypt and  the ,sudan the ,nile passes 
from areas where it flows peacefully and
  quietly1 usually of considerable      
breadth and bounded by fertile lands1   
to others in which it is restricted1    
dashing down steep slopes in  rapids and
 cataracts4 ,a geological examination   
has shown that in  the first case the   
river is flowing over and between       
sedimentary  homogeneous rocks1 such as 
the limestones and sandstones1 while in 
the second instance it has entered      
regions composed of heterogeneous       
igneous and metamorphic rocks1 such as  
the granites1 gneisses and  schists4    
,the production of these rapids is due  
to the combination of  steep slope and  
the difference between harder and softer

 materials1  the rapidly-moving waters  
wearing away those more easily denuded1 
while the compact members remain as     
obstacles to their advance1  and are    
only slowly worn away along joint-planes
 and other lines of  weakness4 ,in the  
,third ,cataract1 hard bars of granite  
rising through  softer gneiss at right  
angles to the river course have produced
 the  main rapids2 elsewhere1 as at the 
,bab el ,kebir1 near ,wadi ,halfa1 the  
river has taken advantage of a thin dyke
 of soft rock traversing an  extremely  
hard diorite1 so that the stream has    
worn a narrow gully  between steep      
rock-walls1 where the intensity of the  
rush of water  is greatly exaggerated   
owing to its being restrained and       
fettered  by the narrowness of the      
passage4 ,in some cases the same result 
has  been produced owing to the         
existence of a line of fracture1 or     
fault1  across the stream1 the waters   
taking advantage of this line of least  
resistance4 ,the general erosion in     

these rapids is accompanied  by great   
local effects where eddies and          
whirlpools are produced1  and the sand  
and rocky fragments act as abrading     
agents4 ,pot-holes  are formed in the   
solid rock1 and rapidly deepened by the 
intense  effects of this nature produced
 during times of flood1 the result      
being splendidly illustrated in some of 
the smaller islands of the  ,first      
,cataract at ,aswan4    ,a river is1 in 
fact1 the main agent combining the      
effects of  transformation and          
reformation1 new strata being produced  
in its  plain tract as the result of the
 eroding activities in its upper        
reaches4 ,much of the detrital material 
is also carried seaward to  form        
deposits of marine sands and muds along 
the shore-lines of the  continents1     
these themselves becoming1 should       
subsequent differential  movement of    
land and sea take place1 the sandstones 
and clays of  future continental areas4 
,but there are other agencies at work as

 transformers on and within  the earth's
 crust4 ,there are in most rocks a      
series of divisional  planes1 which may 
be either vertical or inclined1 and to  
which  the name of joints has been      
given4 ,these may arise from various    
causes4 ,both in sedimentary and igneous
 rocks they are in part  due to         
contraction during consolidation--in the
 former when they  lose their contained 
water1 in the latter when they solidify 
from a  molten condition4 ,joints may   
also be called into being by the effects
  of internal pressures and movements   
within the earth's crust1  such         
structures having been experimentally   
reproduced by ,daubre  in materials     
under stress by torsion and by simple   
pressure4 ,the  granite of ,aswan       
displays such jointing to a marked      
degree1 giving  rise to remarkable hills
 composed of huge boulders of granite   
piled  on one another4                  
,v4--,,chemical ,,transformation ,,of   
,,rocks4      ,besides the mechanical   

effects of river1 rain1 and wind1 other 
changes  whose wide-reaching            
significance cannot be over-estimated1  
are taking  place on and below the      
earth's surface4 ,chemical action is    
slowly  at work producing effects of the
 first importance to man4 ,rain-water   
has the power of absorbing important    
quantities of carbonic acid  gas and    
oxygen from the atmosphere4 ,on the     
average1 rain-water  contains #agg per  
cent by volume of dissolved carbonic    
acid gas1  and #ccgf per cent of        
dissolved oxygen4 ,in passing through   
the soil1  rain-water also absorbs the  
organic acids formed by the             
decomposition  of plant remains4 ,these 
dissolved gases and organic acids render
 rain  an active chemical agent in the  
alteration of rocks1 its effects  being 
conveniently classified under the       
headings3 7#a7 ,oxidation2  7#b7        
,solution2 7#c7 ,formation of           
,carbonates2 and 7#d7 ,hydration4       
7#a7 ,oxidation results in the formation

 of thin crusts on the  surface of      
rocks1 the compounds of manganese and   
iron so frequently  present in them     
being also rusted or hydrated by the    
action of the  rain-water4 ,nothing is  
more striking than the presence of the  
dark  films on the desert limestones in 
regions which are liable to a  certain  
amount of rainfall1 and nothing more    
convincing as to their  origin than     
their absence in those portions of the  
south-western  desert of ,egypt where   
rain is of great rarity4 ,near the      
,nile1 the ,red  ,sea and the           
,mediterranean1 dew may take the part of
 rain in action1  and in a sense the    
results of its activity may appear more 
intense1  as rain is liable to wash away
 the products of its own handiwork4     
7#b7 ,the effects of ,solution are of   
the greatest importance1  limestone     
being soluble to the extent of about #a 
part in #a1jjj in  water saturated with 
carbonic acid4 ,in many limestone       
countries of the  world the solution    

effects are marked by the production of 
underground  caves and channels and in  
some parts of the north-eastern desert  
of  ,egypt1 where chalky limestones are 
the main constituent1 this action  has  
produced remarkable results--large      
caves1 cylindrical channels1  and       
natural bridges being of not uncommon   
occurrence4    7#c7 ,formation of       
,carbonates4 ,owing to the rains in     
,egypt being of very  brief duration1   
but nevertheless extremely active while 
they last1  the soluble material in the 
condition of the unstable bicarbonate   
of lime is carried only a short         
distance1 and losing its loosely        
combined carbonic acid is redeposited in
 the cracks of the rocks1  as veins of  
carbonate of lime1 or as the cementing  
material by  which broken fragments are 
consolidated into compact breccias4     
,this  action may be seen in the cliff  
face south of the ,pyramids1 near the   
,sphinx1 where the sandy limestones     
forming the top of the hill have  been  

attached by the rain containing carbonic
 acid4 ,the calcareous  tests of the    
shells in the sandy limestones have been
 dissolved away1  leaving only the sandy
 internal casts of the shells behind1   
and the  material so removed has been   
redeposited in intricate interlacing    
veins in a clayey band immediately      
below4 ,a vein may sometimes grow  by   
the accretion of successive layers1     
which1 owing to local causes1  such as  
the relative content of iron oxide1     
etc41 may display slightly  different   
colours1 one of the results being the   
production of so  interesting a rock as 
the ,egyptian alabaster1 which is a     
carbonate  of lime4 ,as a rule1 the term
 alabaster is applied to the sulphate   
rather than to the carbonate of lime4   
,probably much carbonate of  lime is    
also carried in solution to the sea1 and
 there forms the  source of the material
 which hundreds of living animals seize 
upon  for the production of the shells  
in which they dwell4 ,i was much  struck

 last year1 during a journey from the   
,pyramids to ,wasta1 to  note how the   
oyster-beds of one age 7the ,pliocene7  
formed themselves  upon oyster-beds of a
 long preceding period 7the ,eocene71   
probably  on account of the greater     
amount of carbonate of lime at those    
localities1 present owing to solution of
 the earlier shell-structures4    ,that 
veins of carbonate of lime should be    
present in limestone  districts is1 in  
view of the above statements1 not       
surprising1  but it does appear somewhat
 startling at first sight1 to find      
marked deposits of carbonate of lime    
lining the floors and sides of          
torrent-beds in districts entirely      
composed of igneous or volcanic  rocks  
of complicated mineral structure4       
,experience has shown1  however1 that   
the lime silicates1 so abundant in the  
more basic  members of the igneous      
series1 such as diabases and diorites1  
are  liable to the attack of the        
rain-waters containing carbonic acid1   

carbonate of lime being produced by the 
reaction4    7#d7 ,of the results of    
,hydration1 the most striking examples  
in ,egypt  are the formation of kaolin  
near ,aswan1 due to the absorption of   
water  by the felspars of the granitic  
and gneissose rocks1 and the thick  zone
 of decomposition 7kaolinic7 products1  
which was cut through in  excavating the
 navigation canal in the syenite which  
forms the main  rock at that locality4  
,the total effect of all the            
above-mentioned meteorological          
influences  results in the weathering of
 the rock-surface1 involving the        
softening  and crumbling of the harder  
materials1 but sometimes leading to  the
 solidification of materials previously 
loosely aggregated by  substances left  
as cementing agents when the water      
containing them  in solution has        
evaporated4    ,in addition to the      
various direct results of the           
meteorological  activities upon the     
earth's surface1 there are others which 

indicate more subtle changes4 ,perhaps  
amongst the most interesting  of these  
is the formation of concretions--bodies 
composed of one  material aggregated in 
more or less rounded or irregular form  
in a  rock of another composition4      
,among the most interesting and abundant
  of these are the layers of flint1     
which form bands of strikingly  parallel
 character in the limestones of ,upper  
,egypt4 ,these have not  yet been       
submitted to the detailed study which   
similar concretions  have received in   
,europe1 but there is little doubt that 
they1  in large measure1 represent the  
aggregation of gelatinous silica  round 
decomposing organic materials1 the      
shells of organisms and the  framework  
of siliceous sponges often forming their
 centre4 ,in some  cases1 as in the     
fossil trees1 the replacement appears to
 have taken  place molecule by molecule1
 as the outlines of every cell of the   
once  woody fibre are now replaced in   
silica4 ,by a well-known transition1    

this once gelatinous material has now   
become one of the most solid  of        
substances4    ,ferruginous concretions1
 composed of oxide of iron1 are present 
in  many of the ,egyptian sandy clays1  
some of the beautifully-tinted  purple1 
yellow and red ochres being found in    
this form2 and  the natives collect them
 for the use of the women as ornamental 
coloration4    ,of greater importance to
 the world at large are the gradual     
changes  which vegetable matter         
7collected under specially favourable   
circumstances free of all sandy and     
clayey admixture7 has undergone  through
 vast periods of time1 causing the slow 
evolution of the  oxygen1 hydrogen and  
nitrogen1 originally present1 with a    
gradual  predominance of the carbon4    
,this passage from vegetable matter to  
coal  has been noted in ,egypt in       
connection with the ,nubian sandstone1  
beds of carbonaceous material deserving 
the name of lignite or  even bituminous 
coal having been found at various       

localities4 ,the  deposits found up to  
the present time are of such tenuity    
that it  is not possible on the evidence
 available to express optimistic        
opinions as to the probable occurrence  
of workable coal in ,egypt1  but still  
they are of sufficient interest to be   
kept constantly in  mind while the      
,geological ,survey is prosecuting its  
researches4 ,from  time to time the     
finding of coal-seams has been reported 
at ,edfu1  in ,kharga1 at ,saqiet el    
,teir and ,abu ,radham#g in the ,eastern
 ,desert1  but the efforts hitherto made
 have resulted in failure4    ,the      
evidence thus far available shows that  
great rivers were entering  the sea in  
,nubia during an early geological period
 7the ,cretaceous71  typical fresh-water
 shells having been found south of      
,aswan covered  with marine worm-tubes2 
leaf-imprints are abundant in some of   
the sandy layers1 and in isolated       
instances they have collected  in       
sufficient quantity to give rise to     

lignite and bituminous  coal-layers of  
extreme thinness1 showing that this     
interesting  and important change has   
taken place1 at least to some extent1   
in ,egypt itself4 ,the study of         
coal-producing regions tends to show    
that the change to coal of high         
commercial value requires not only      
conditions favourable to the loss of the
 more volatile gases1 but  also that the
 beds must have been involved in great  
earth-movements1  which have hastened   
the tendency to their being enriched in 
carbon1  both favourable conditions of  
deposition and marked disturbance of    
the strata being thus required to obtain
 the much-desired result4    ,other     
internal chemical activities are at     
work1 producing changes  which are still
 the cause of debate and earnest study4 
,the origin of  petroleum must          
undoubtedly be traced to chemical       
transformations of a  complicated       
character1 if we may judge by the number
 of experimental  methods which yield   

petroleum as a product4 ,all opinions   
agree that  the mineral oil is derived  
by some form of chemical action1 though 
whether it arises from the decomposition
 of organic remains or whether  it be of
 inorganic origin is still matter of    
dispute4 ,geological  students have on  
the whole ranged themselves on the side 
of the  first-named view1 pointing out  
that the petroleum fields are all       
associated with sedimentary strata1     
whether sands or limestones4 ,the       
inorganic view has been held as         
tenaciously by a number of men          
experienced in the search for oil1 and  
it is capable of argument  that sulphur 
dioxide and sulphuretted hydrogen1 if   
being produced  simultaneously1 may     
result in the alteration of limestone to
 gypsum1  free sulphur and petroleum    
being also obtained in the reaction4    
,in this connection it is interesting to
 note that gypsum1 sulphur  and         
petroleum are associated at ,jemsa1 on  
the ,gulf of ,suez4    ,one of the most 

interesting features in connection with 
petroleum is  the phenomenon presented  
in most oil-fields of oil-wells         
separated  perhaps by only thirty metres
 emitting oil under pressure at the     
same time2 also the great pressures     
indicated by the remarkable  fountain   
flows which are of constant occurrence  
in the principal  petroleum fields4#h   
,,vi4--,,the ,,formation ,,of ,,igneous 
,,rocks4      ,the external and internal
 transforming agents are therefore of   
the deepest interest and of the highest 
economic importance1  and the further   
study of the deep-seated changes leads  
directly  to a consideration of the     
formation and sustained activity of the 
molten materials which find their main  
present-day expression in the  phenomena
 of volcanoes4 ,their extension in the  
past is also revealed  by the wearing   
hand of time in the wide distribution of
 coarsely  crystalline granites and     
other igneous rocks1 once deep-seated1  
but now exposed in regions which are    

either the cores of ancient  continents 
or centres of exceptional deformation4  
,igneous action and movements of the    
earth's crust stand in intimate         
relation to one another1 a point which  
has been clearly stated by  ,dr4        
,harker#i as follows3--8,setting aside  
operations conducted in  hypothetical   
intercrustal magma-basins1 or generally 
in the unknown  depths of the earth's   
crust1 we recognize the actual          
manifestations  of igneous action       
chiefly in the forcing outward of molten
 magmas from  a lower to a higher level 
within the crust or through the crust to
 the  surface40 ,this study has led     
directly to the recognition of three    
phases of igneous action1 of which two  
are intrusive1 being phases in  which   
the molten materials are raised from a  
lower to a higher level  within the     
earth's crust1 and an extrusive phase1  
in which these  materials are raised to 
the surface and poured out there as     
lavas4    ,study in all parts of the    

world has further shown that these      
events  follow a definite sequence or   
cycle of igneous activity1 volcanic     
phenomena marking its commencement1     
followed by the movement of  deep-seated
 igneous molten magmas 7representing the
 plutonic phase71  and closing with a   
number of minor intrusions1 which may   
seam both the  volcanic1 plutonic1 and  
sedimentary strata4 ,egypt clearly      
illustrates  this remarkable succession1
 and thus gives additional grounds for  
believing that it is of fundamental     
importance4 ,volcanic activity  was     
developed on a gigantic scale when the  
most ancient sediments  of ,egypt1 now  
forming the folded and altered slates   
and schists  of the ,red ,sea hills1    
were being laid down4 ,to this part of  
the  cycle belong some of the most      
interesting rocks of the country1  the  
imperial porphyry of ,dokhan1 the dark  
andesites that crown  the highest       
summits in ,sinai1 and the country-rock 
in which some  of the most ancient of   

,egypt's gold-mines are situated4 ,here1
  too1 belong the banded and columnar   
lavas of the ,sixth ,cataract1  and the 
fragments of volcanic rocks which play  
an important part in  the characteristic
 conglomerates of the ,eastern ,desert4 
,still more conspicuous is the phase of 
plutonic activity1 vast  masses of      
granite1 diorite1 and other highly      
crystalline rocks  as molten magmas     
having been in contact with or intruded 
into the  overlying sediments and       
volcanic materials4 ,from ,sinai to the 
,sudan  there is a geographical complex 
due to the intermingling of these       
deep-seated igneous rocks with the older
 and metamorphosed volcanic  and        
sedimentary members4 ,desolate volcanic 
hills of dull-green shade1  whose sides 
are covered with weathered debris of    
irregular outline1  alternate with broad
 plain1 out of which rise rounded masses
  of granite1 or with mountain ranges1  
whose precipitous sides and  serrated   
outlines constitute some of the most    

striking features of  the ,red ,sea hill
 scenery4    ,the final phase1 that of  
the minor intrusions1 is admirably      
illustrated in ,egypt1 large areas of   
the desert consisting of low  ridges    
formed of parallel bands or dykes of    
hard rocks1 which have  seamed the      
softer granite1 the latter having       
subsequently been worn  down by erosion4
 ,in other cases the dyke is of more    
basic composition  and more easily      
denuded than the adjacent rocks4        
,when these evidences of past igneous   
activity are examined1 they  reveal the 
interplay of such varied and complicated
 chemical and  physical effects that a  
large volume would be required to set   
forth  the great body of facts observed4
 ,of these only a bare statement of  the
 most incomplete order must suffice4    
,igneous rocks are of very  variable    
chemical composition1 and for the       
purposes of discussion of  their complex
 relationships have been subdivided into
 three series  according to the amount  

of silica they contain1 viz43--,the     
,acid  ,rocks with #ej to #gj per cent  
silica2 ,the ,intermediate ,rocks with  
#ej  to #fj per cent silica2 ,the ,basic
 ,rocks under #ej per cent silica4 ,as a
  whole1 the igneous rocks are compounds
 of the silicates of alumina1  magnesia1
 lime1 potash and soda1 with oxide of   
iron2 the silicates  of alumina1 soda   
and potash are most abundant at the acid
 end of  the scale1 and those of lime1  
magnesia1 with the oxides of iron  and  
phosphates at the basic extreme4 ,in    
consequence1 the basic  rocks are       
usually darker in colour and heavier    
than the more acid  varieties4 ,not only
 have the igneous rocks a varying       
composition1  but also a varying        
structure depending on the differences  
of  origin and position4 ,we may note   
their history as involving several      
stages1 viz43--7#a7 ,solidification from
 the initial molten magma2  7#b7        
,deformation when under the influence of
 great earth pressures2  7#c7           

,transformation under the meteorological
 influences1 at or near  the earth's    
surface4 ,in addition there are the     
contact alterations  produced near their
 junctions with the overlying strata1   
both within  themselves and in the beds 
affected by the molten material4    ,a  
molten magma varies greatly in its      
behaviour according to  its position1   
the solidification of that portion which
 remained  deep-seated in the hidden    
reservoir beneath the earth's crust     
taking place slowly and imperceptibly4  
,a rock such as granite is  not formed  
suddenly by instantaneous cooling1 but  
step by step  individual minerals are   
crystallized from the complex solution1 
and  tend to develop as regular and     
often most beautiful crystals4 ,it  is a
 source of surprise to most to learn    
that the greater number  of mineral     
substances1 if free to develop from     
solution without  external hindrances1  
tend to form solid bodies which are     
fashioned on  geometrical principles1   

constituting one of the most interesting
 and  mysterious problems with which    
scientific thought has to deal4 ,the    
minerals1 as a rule1 tend to crystallize
 out directly in the order  of their    
basicity1 the oxides of iron with their 
eight-sided crystals  being among the   
first1 so that their octahedral outlines
 are usually  well preserved4 ,the other
 minerals of the rocks follow in        
succession2  sometimes complicated      
intergrowths occur owing to two crystals
 of  different composition starting     
their formation at the same time in the 
same portion of the solution4 ,finally1 
the last-formed minerals have  to occupy
 the interspaces left by their          
consolidated neighbours1 and  in the    
more acid rocks this unenviable position
 is usually reserved  for the free      
silica1 forming quartz4 ,these          
deep-seated masses1  slowly solidified  
and entirely crystalline in their       
structure1  have been called the        
,plutonic rocks1 the example familiar to

 all  dwellers in ,egypt being the red  
,aswan1 or monumental granite4 ,in it1  
the felspars and micas or hornblendes   
present tend towards their  true crystal
 form1 while the quartz occupies the    
interspaces4    ,intermediate between   
the extruded volcanic rocks1 and the    
highly  crystalline varieties of the    
internal reservoirs of molten material1 
are the dyke or hypabyssal rocks1 which 
as narrow vertical or nearly  vertical  
intrusions pass in all probability from 
the deep-seated  source towards the     
surface of the earth1 when they reach it
 giving  rise to volcanic effects4 ,the 
dykes have a tendency to be parallel to 
one another1 and in some regions are the
 most conspicuous features1  if harder  
than the surrounding rock giving rise to
 marked ridges  separated in many cases 
by comparatively shallow valleys4 ,not a
 few  of the main summits in the ,red   
,sea hills and ,sinai have assumed their
  present form and outline owing to the 
unequal denudation of one of  these hard

 bands1 while many an ascent1 which     
otherwise would have  been by no means  
free from danger1 is simplified by the  
formation of  gullies due to the wearing
 away of the softer and more basic      
members  of this series4    ,in the     
hypabyssal varieties1 as well as in     
surface flows1 an  examination of       
hand-specimens often reveals the        
presence of  larger crystals 7usually   
termed porphyritic crystals7 scattered  
in a ground-mass in which no definite   
structure is visible except  under the  
microscope4 ,these may in part have been
 formed before  the molten magma of the 
rock had begun its upward ascent1 but in
  general they and the finer-grained    
base1 have crystallized under  similar  
conditions4 ,examinations of the        
ground-mass microscopically  also shows 
it to be entirely crystalline in its    
nature1 but the  individual components  
are of very small size4    ,in the      
extruded volcanic rocks1 on the other   
hand1 the porphyritic  crystals are     

probably of much earlier date than the  
ground-mass in  which they are present1 
the latter being solidified             
above-ground1  where cooling was rapid1 
pressure suddenly reduced1 and many of  
the gaseous constituents were free to   
escape readily4 ,as crystals  require a 
certain temperature and a slow          
liberation of the heat for  their       
formation1 in many volcanic rocks the   
rapid cooling results  in the production
 of a glass instead of a crystalline    
aggregate1  so that the presence of a   
glassy matrix is in itself evidence of a
  quick loss of heat4                   
,,vii4--,,the ,,formation ,,of          
,,metamorphic ,,rocks4      ,all        
materials1 both sedimentary and igneous1
 composing the earth's  crust1 are      
liable to be involved in movements of   
deformation1 becoming  subject to       
pressures and chemical agencies1 which  
are often intense  in character and     
productive of far-reaching internal     
changes4 ,the  result is the formation  

of a series of rocks1 which may be of   
divers  origins1 but which having lost  
their original characteristics1  may be 
grouped as metamorphic4 ,by the action  
of compression  and dislocation not only
 are the major masses folded or broken1 
but their individual constituents are   
brought into new relations  both as     
regards their external conditions and   
internal molecular  arrangement4 ,where 
lateral pressure has been active as     
regards the  finer-grained rocks1 such  
as clays1 the individual particles      
arrange  themselves with their longer   
axes at right angles to the pressure1   
the result being the production of a    
fissile structure or cleavage1  totally 
distinct from the original              
bedding-planes of the strata4    ,clays 
under such circumstances pass into      
slates1 in which no very  definite      
mineral banding is observed1 or into    
schists1 in which there  is a tendency  
for the separate minerals1 such as mica 
and quartz1 to  have a pseudo-stratified

 appearance1 though the individual      
layers1  if closely examined1 are found 
to be lenticular1 not parallel in       
shape4 ,these schists and slates are    
developed on a large scale in  the ,red 
,sea hills and ,sinai4    ,the extent to
 which compression and tension has been 
carried in  these ancient sedimentary   
strata is well indicated in ,sinai1     
where  rounded pebbles of quartz have   
been fractured1 the two broken parts    
somewhat separated1 and the whole       
re-cemented in a schistose matrix4      
,in many instances1 besides mechanical  
stress1 another factor of  metamorphism 
of rocks has to be invoked to explain   
the phenomena  observed4 ,mineral       
changes take place in these rocks which 
are due  to the superadding of thermal  
action1 consequent on their direct      
contact with molten masses of granitic  
and other plutonic rocks4 ,in  ,sinai1  
for instance1 new minerals are called   
into existence by  these contact        
effects1 members of the andalusite      

group1 which  are formed at high        
temperatures1 being produced near the   
junctions1  garnets being present in the
 mica-schists in a zone somewhat further
  removed from the contact area1 while  
beyond these is a belt where the  slaty 
strata show only traces of the formation
 of the new minerals  in the presence of
 ill-defined knots1 or segregations     
forming the  so-called 8,knotenschiefer0
 of the ,germans4    ,it is possible to 
trace the influence of these contact and
 dynamic  effects1 not only in the      
sedimentary rocks1 but also in those of 
plutonic origin4 ,an excellent example  
of such changes1 known as  foliation1   
can be observed in the ,dal ,cataract1  
where a granite is  present containing  
large crystals of red felspar4 ,it is   
possible  to trace the change of this   
rock into a variety which instead  of   
being massive1 is banded1 the bands     
containing the larger red  felspars all 
tending to lie in one plane4 ,these are 
not parallel1  but lenticular1 certain  

of the minerals1 especially the         
felspars1  remaining comparatively      
unaffected as 8eyes10 round which the   
other minerals appear to sweep4 ,the    
quartz in many instances is  found to be
 crushed into a mosaic of small grains1 
and the plates  of mica have been       
dragged out and separated from one      
another by  the shearing4 ,these rocks1 
having a general composition resembling 
the granites1 have been termed gneisses1
 and in some cases1 similar  effects    
have been produced by the intrusion of  
veins of granite along  the horizontal  
planes of a more basic rock already     
banded4 ,this result  is well seen in   
the ,third ,cataract1 where a foliated  
rock composed of  a white felspar and   
mica has been pierced by veins of highly
 quartzose  granite1 which has then     
spread along the lamin of the older     
member4    ,similarly in ,sinai1 the    
granite1 where in contact with the      
schistose  sedimentary beds1 has in     
certain favourable localities penetrated

  between the schistose layers1         
producing a banded rock which approaches
  a gneiss in character4    ,in ,egypt1 
we are not at present acquainted with   
such gigantic  overfolding1 fracture1   
and pushing of whole masses of strata   
one  over the other1 as have been       
studied1 for example1 in the            
,north-,west  ,highlands of ,scotland1  
but there is in ,egypt itself1 a vast   
series  of gneisses1 crystalline        
schists1 marbles and dolomites whose    
origin is but dimly understood1 and     
which may represent changes  long       
anterior those exhibited by the ancient 
rocks of which we have  been speaking4  
,developed in the untrodden wastes of   
the ,sudan1 in  the wilder stretches of 
the ,cataracts1 in the desolate regions 
of  the ,etbai ,desert of ,egypt1 their 
study is attended with difficulty  and  
all our hypotheses must depend on the   
comparison of isolated  specimens with  
similar rocks from more favoured        
regions4                                

,,summary4      #a4--;,every rock       
originates either from the              
solidification of  molten material or of
 sediments1 these constituting the      
,igneous and  ,sedimentary ,rocks       
respectively4    #b4--,these may undergo
 deformation due to movements of the    
earth's  crust1 such movements according
 to their intensity determining  the    
re-arrangement of the constituents with 
the development of new  structures1     
producing the ,metamorphic ,rocks4      
#c4--,these varied rocks1 when exposed  
at the earth's surface1 are  brought    
under the influence of the agents of    
transformation1 such as  frost1         
contraction and expansion due to        
variations of temperature1  the         
mechanical action of rain1 sand borne by
 wind1 and running  water in the form of
 streams4 ,in addition to these purely  
physical  activities are others of a    
chemical nature1 either proceeding from 
changes outside the terrestrial surface 
7carbonic acid dissolved in  rain1      

etc471 or from processes operating      
within the earth's crust  7production of
 petroleum1 coal1 mineral veins1 etc474 
#d4--,the chemical and physical         
activities deep within the earth's      
crust result in the formation of the    
plutonic rocks solidified from  molten  
solutions1 intimately associated with   
them being the external  manifestations 
of the working of these hidden forces as
 revealed in  volcanoes and their       
associated phenomena4    #e4--;,by the  
surface changes on the consolidated     
igneous and other  rocks1 the materials 
are supplied for the formation of some  
of the  members of the sedimentary      
series1 the sands and clays1 while the  
limestones in large measure owe their   
origin to the property possessed  by    
living animals of constructing shells   
from the carbonate of lime  brought in  
solution to the oceans1 etc41 these     
shells1 after the death  of the animals1
 contributing to the formation of the   
calcareous rocks4      ,,footnotes3     

,footnote #a3 ,in geology1 the term rock
 is applied alike to the soft  and hard 
materials composing the earth's crust1  
as sands may pass  into solid           
sandstones1 soft muds become the most   
tenacious of clays1  and hard basalt    
originate as a molten lava4    ,footnote
 #b3 ,this statement may not absolutely 
apply to ,cairo itself1  seeing that in 
the disturbed region of ,abu ,roash     
sandstone is actually  at the surface1  
and the clays are less conspicuously    
developed than  is the case to the      
south4    ,footnote #c3 ,figs4 #a1 #b   
and #d are based on photographs of      
localities  in ,great ,britain and      
,ireland taken for the ,geologists'     
,association  collection of photographs4
    ,footnote #d3 ,farafra is an        
exception to this rule1 the depression  
being due to the wearing away of soft   
,cretaceous beds higher than  the       
sandstone4    ,footnote #e3 ,the        
well-known ,petrified ,forests4         
,footnote #f3 ,from information given by

 ,mr4 ,harding ,king4    ,footnote #g3  
,at ,abu ,radham a dark layer of purple 
iron ochre seems  to have been the cause
 of the investigation4    ,footnote #h3 
,for further details1 see my paper      
8,petroleum3  ,its occurrence and       
origin10 ,cairo ,scientific ,journal1   
,no4 #dh1  pp4 #bje-bah4    ,footnote   
#i3 8,the ,natural ,history of ,igneous 
,rocks10 p4 #bc4                        
,,short ,,catalogue                     
,,of ,,the                      ,,maps1 
,,plans1 ,,and ,,publications           
,,issued ,,by ,,the                     
,,survey ,,department1 ,,ministry ,,of  
,,finance1 ,,egypt4                     
99 99 99 99 99                          
,,maps ,,and ,,plans4                   
99 99 99 99 99    ,the following is a   
general list of the maps and plans      
offered for  sale by the ,survey        
,department4 ,a booklet giving details  
of all sheets  printed may be obtained  
free1 on application either personally  
or  by letter at the ,headquarters of   

the ,department1 ,giza 7,mudiria71  or  
at the ,geological ,museum1 ,public     
,works ,ministry ,gardens1 ,cairo1      
where all maps and plans are for sale1  
or through any bookseller4    ,except   
where specially stated1 the price of    
each map-sheet is #ej  milliemes on     
paper1 and #fe milliemes on cloth1 and  
they are sent  post free by the         
,department4    ,the reference marks    
denote3 7997 map is in ,arabic only2 77 
map is in  ,english only2 7997 map bears
 place-names both in ,arabic and        
,english2  7997 77 map can be obtained  
either in ,arabic or ,english4          
,town ,maps4      ,the following list   
gives particulars of the maps published4
 ,the  map of ,alexandria1 on the scale 
of #a3a1jjj will be completed during    
#aiaa4 ,the survey of ,cairo on the     
scale of #a3a1jjj is in progress4       
,cairo 79971 #cj sheets1 scale #a3a1jjj 
7in preparation74      ,alexandria 79971
 #adg sheets1 scale #a3a1jjj4           
,general map of ,alexandria             

,municipality 7,french and ,arabic71 #aj
    sheets1 scale #a3f1jjj4      ,mit   
,ghamr 79971 #d sheets1 scale #a3a1jjj4 
,mansura 79971 #af sheets1 scale        
#a3a1jjj4      ,suez 79971 #bj sheets1  
scale #a3a1jjj4      ,suez 79971 #a     
sheet1 scale #a3b1ejj4      ,sohag 79971
 #f sheets1 #a3a1jjj4      ,tanta 79971 
#ae sheets1 scale #a3a1jjj4      ,girga 
79971 #f sheets1 scale #a3a1jjj4        
,aswan 79971 #bc sheets1 scale #a3a1jjj4
      ,port ,said 7in ,french71 #a      
sheet1 scale #a3e1jjj4      ,zagazig    
79971 #bj sheets1 scale #a3a1jjj4       
,damanhur 79971 #ad sheets1 scale       
#a3a1jjj4      ,benha 79971 #be sheets1 
scale #a3a1jjj4                         
,cadastral ,maps4      ,these are maps  
of the villages showing each hod and    
plot of  land4 ,they are printed in     
,arabic only4 ,in ordering1 the name of 
the village and the numbers of hod and  
plot should be given4 ,the  following   
list gives the particulars of the maps  
for each mudiria  7province73--         

,beheira mudiria 79971 #c1cjj sheets1   
under survey1 scale #a3b1ejj4           
,gharbia mudiria 79971 #c1dfj sheets1   
scale #a3d1jjj and #a3b1ejj4            
,daqahlia mudiria 79971 #b1bcg sheets1  
scale #a3b1ejj4      ,sharqia mudiria   
79971 #b1igd sheets1 scale #a3b1ejj4    
,menufia mudiria 79971 #b1agc sheets1   
scale #a3d1jjj and #a3b1ejj4            
,qaliubia mudiria 79971 #ggh sheets1    
scale #a3b1ejj4      ,giza mudiria 79971
 #gff sheets1 scale #a3d1jjj4           
,fayum mudiria 79971 #b1bfc sheets1     
scale #a3b1ejj4      ,beni ,suef mudiria
 79971 #idb sheets1 scale #a3b1ejj4     
,minia mudiria 79971 #a1fce sheets1     
scale #a3b1ejj4      ,assiut mudiria1   
including ,kharga ,oasis 79971 #b1bgc   
sheets1 scale    #a3b1ejj4      ,girga  
mudiria 79971 #a1cac sheets1 scale      
#a3b1ejj4      ,qena mudiria 79971      
#a1efh sheets1 scale #a3b1ejj4          
,aswan mudiria 79971 #a1jgf sheets1     
scale #a3b1ejj4                         
,topographical ,maps4      ,scale       

#a3aj1jjj 7#aj cm4  #a kilometre2 #fc   
inches  #a mile74--,the  names on these 
maps are in most cases in ,arabic and   
,english4 ,the  following table shows   
the number of sheets published3--       
,beheira mudiria 79971 #bfj sheets4     
,gharbia mudiria 79971 #bac sheets4     
,sharqia mudiria 79971 #bi sheets4      
,daqahlia mudiria 79971 #aa sheets4     
,menufia mudiria 79971 #gc sheets4      
,qaliubia mudiria 79971 #fe sheets4     
,giza mudiria 79971 #ij sheets4         
,fayum mudiria 79971 #abf sheets4       
,beni ,suef mudiria 79971 #ba sheets4   
,assiut mudiria1 including ,kharga      
,oasis 79971 #gb sheets4      ,aswan    
mudiria 79971 #fc sheets4      ,aswan or
 ,first ,cataract 771 #f sheets4        
,the ,nile ,valley from ,aswan to       
,korosko771 #cf sheets 7paper only1     
#be milliemes each74    ,scale #a3be1jjj
 7#d cm4  #a kilometre2 #be inches  #a  
mile74--,a  provisional map of ,northern
 ,gharbia has been published on this    
scale1  pending the publication of the  

#a3aj1jjj sheets of this area4 ,there   
are #ia sheets4    ,scale #a3ej1jjj 7#b 
cm4  #a kilometre2 #ac inches  #a       
mile74--,these  maps are printed in     
three colours4 ,names are given in      
,english1  and as a rule in ,arabic as  
well4 ,this series is completed for the 
whole of the cultivated area of the     
,nile ,valley and ,delta4 ,there  are   
#ade sheets4    ,scale #a3a1jjj1jjj 7#a 
cm4  #aj kilometres2 #a inch  #af       
miles74--,the  six sheets of this map1  
covering the whole of ,egypt1 have now  
been  published4 ,the names are in      
,english4 ,the price of each sheet is   
#ej  and #fe milliemes for paper and    
cloth editions respectively1 or the     
whole can be obtained mounted on cloth1 
varnished1 and fitted with  rollers for 
#eej milliemes4                         
,special ,maps on ,various ,scales4     
,map of the ,delta 771 #d sheets1 scale 
#a3bjj1jjj4 ,price1 #ge milliemes    per
 sheet1 or the complete map mounted on  
cloth1 varnished and fitted    with     

rollers1 #gjj milliemes4      ,lower    
,egypt and the ,fayum1 #aijd 7latest    
edition7 771 #a sheet1    scale         
#a3ejj1jjj4      ,lower ,egypt1 showing 
lines of communication 771 #a sheet1    
scale    #a3ejj1jjj4      ,northern     
,gharbia 79971 #a sheet1 scale          
#a3bjj1jjj4      ,kharga ,oasis 771 #a  
sheet1 scale #a3ejj1jjj4      ,dakhla   
,oasis 771 #a sheet1 scale #a3ejj1jjj4  
,baharia ,oasis 771 #a sheet1 scale     
#a3ejj1jjj4      ,farafra and ,iddalia  
,oases 771 #a sheet1 scale #a3ejj1jjj4  
,provisional map of the ,eastern ,desert
 of ,egypt1 ,east ,qena-,aswan to       
,red ,sea 771 #bj sheets1 scale         
#a3ajj1jjj4      ,provisional map of the
 ,eastern ,desert of ,egypt1 between    
,qus1 ,sayala    and ,red ,sea 771 #b   
sheets1 scale #a3ejj1jjj4               
,provisional map of a part of the       
,eastern ,desert ,oilfield 771    #a    
sheet1 scale #a3ajj1jjj4 ,price1 #ajj   
milliemes on paper and #aej    milliemes
 on cloth4      ,provisional map of a   

part of the ,eastern ,desert ,oilfield1 
showing    registered prospecting areas 
771 #a sheet1 scale #a3ajj1jjj4 ,price1 
#ajj milliemes on paper and #aej        
milliemes on cloth4      ,red ,sea and  
,sinai ,oilfield1 showing registered    
prospecting areas    771 #a sheet1 scale
 #a3caf1hjj4 ,price1 #ajj milliemes on  
paper and    #aej milliemes on cloth4   
,jemsa ,oil ,zone 771 #a sheet1 scale   
#a3ge1jjj and #a3bej1jjj4 ,price1    #ej
 milliemes4      ,mersa ,matruh chart   
771 #a sheet1 scale #a3d1ejj4           
,mersa ,matruh topographical map 771 #a 
sheet1 scale #a3aj1jjj4      ,mersa     
,matruh and ,ras ,allam ,rum 771 #b     
sheets1 scale #a3be1jjj4                
,aqaba-,rafa1 #aijf 79971 #c sheets1    
scale #a3ajj1jjj4      ,aqaba-,rafa1    
#aijf 7997 771 #a sheet1 scale          
#a3ejj1jjj 7paper1 #be    milliemes2    
cloth1 #dj milliemes74      ,the ,nile  
,valley from ,aswan to ,sudan boundary  
771 #a sheet1 scale    #a3bej1jjj4      
,port d',alexandrie 7,french71 #c       

sheets1 scale #a3d1jjj4                 
,wall-,maps1 for use in ,schools4       
,the price of each map is #gjj          
milliemes1 except that of the           
,mediterranean ,basin1 which is #ejj    
milliemes4 ,each map is mounted on      
cloth1 varnished1 and fitted with       
rollers4 ,the following list gives  the 
maps published and in preparation3--    
,africa 7physical7 79971 scale          
#a3f1jjj1jjj4      ,africa 7political7  
79971 scale #a3f1jjj1jjj4      ,the     
,nile ,basin 7997 771 scale             
#a3b1ejj1jjj4      ,egypt 7997 771 scale
 #a3gej1jjj4      ,the ,delta and the   
,fayum 79971 scale #a3bjj1jjj4          
,mediterranean ,basin 79971 scale       
#a3c1jjj1jjj4      ,western ,europe and 
the ,british ,isles 79971 scale         
#a3a1ejj1jjj4      ,asia 7physical7     
79971 scale #a3f1jjj1jjj4      ,asia    
7political7 79971 scale #a3f1jjj1jjj4   
,europe 7physical7 79971 scale          
#a3c1jjj1jjj4      ,europe 7political7  
79971 scale #a3c1jjj1jjj4      ,the     

,world 7997 7,mercator's projection74   
,the ,hemispheres 7,eastern and         
,western7 7,airy's projection7          
,british ,isles1 scale #a3gej1jjj4      
,north ,america 7997 7physical7         
#a3f1jjj1jjj4      ,north ,america 7997 
7political7 #a3f1jjj1jjj4    ,,in       
,,preparation3--      ,south ,america   
7physical7 #a3f1jjj1jjj4      ,south    
,america 7political7 #a3f1jjj1jjj4      
,geological ,maps4      ,geological map 
of ,egypt1 scale #a3a1jjj1jjj4 ,english4
 ,six sheets1  #gj  #eh cm4 ,price1 #ajj
 milliemes per sheet4 ,complete map1    
mounted  on cloth1 varnished and fitted 
with rollers1 #hej milliemes4           
,geological map of ,egypt1 scale        
#a3b1jjj1jjj4 ,english4 ,one sheet1  #fh
  #fg cm4 ,price1 #bjj milliemes on     
paper1 and #cjj milliemes  mounted on   
cloth and fitted with rollers4    ,a    
number of maps have been published in   
the various ,geological  reports4       
,further information may be obtained    
under the respective  headings in the   

list of ,geological ,reports1 pp4 ,v and
 ,,vi4                                  
,,publications4                         
99 99 99 99 99      ,the following is a 
general list of the publications of the 
,survey  ,department1 and a few others  
which are for sale at the ,headquarters 
of the ,department1 ,giza 7,mudiria71   
and at the ,geological ,museum1  ,public
 ,works ,ministry ,gardens1 ,cairo4 ,a  
booklet giving full details  can be     
obtained1 on application either         
personally or by letter4    ,except     
where specially stated1 the publications
 are #hvo1 and in  ,english1 and are    
supplied post free by the ,department4  
,they can also  be obtained through any 
bookseller4                             
,archology4                             
,,arch,,ological ,,survey ,,of ,,nubia4 
,,bulletin #a4--;,dealing with the work 
7archological and anatomical7  from     
,september #bj to ,november #cj1 #aijg4 
,english4 #ci pp41 #bg  illustrations4  
7,out of print74    ,,bulletin          

#b4--;,dealing with the work            
7archological and anatomical7  from     
,december #a1 #aijg1 to ,march #ca1     
#aijh4 ,english4 #fi pp41 #eb           
illustrations4 ,price1 #ajj milliemes4  
,,bulletin #c4--;,dealing with the work 
7archological and  anatomical7 from     
,october #a to ,december #ca1 #aijh4    
,english4 #eb pp41  #e illustrations4   
,price1 #ajj milliemes4    ,,bulletin   
#d4--;,dealing with the work            
7archological and  anatomical7 from     
,january #a to ,march #ca1 #aiji4       
,english4 #bh pp41  #b illustrations4   
,price1 #ajj milliemes4    ,,bulletin   
#e4--;,dealing with the work            
7archological and  anatomical7 from     
,october #a to ,december #ca1 #aiji4    
,english4 #ce pp41  #e illustrations4   
,price1 #ajj milliemes4    ,,bulletin   
#f4--;,dealing with the work            
7,archological and  anatomical7 from    
,january #a to ,april #ae1 #aiaj4       
,english4 #cj pp41  #h illustrations4   
,price1 #ajj milliemes4    ,,annual     

,,report ,,of ,,the ,,arch,,ological    
,,survey ,,of ,,nubia1 ,,season         
#aijg-h4 ,,vol4 ,i3 by ,,george ,a4     
,,reisner4 ,price1 with volume of       
plates1  ,l4,e4 #b4    ,,annual ,,report
 ,,of ,,the ,,arch,,ological ,,survey   
,,of ,,nubia1 ,,season  #aijg-h4 ,,vol4 
,,ii3 ,report on the ,human ,remains1 by
 ,dr4 ,g4 ,,elliot ,,smith1  ,f4,r4,s41 
and ,dr4 ,f4 ,,wood ,,jones4 ,price1    
with volume of plates1 ,l4,e4 #b4       
,,phil1--,,report ,,on ,,the ,,island   
,,and ,,temples ,,of1 by ,,capt4 ,h4 ,g4
 ,,lyons1  with introductory note by ,w4
 ,e4 ,,garstin4 #ahif4 ,english4 #fg    
pp41  #gh illustrations4 7,out of       
print74    ,,phil1--,,report ,,on ,,the 
,,island ,,and ,,temples ,,of1 by       
,,capt4 ,h4 ,g4 ,,lyons4 #aijh4         
,english4 #dto1 #cb pp41 #ad            
illustrations4 ,price1 #bjj milliemes4  
,geography4      ,,river ,,nile ,,and   
,,its ,,basin--,,physiography ,,of      
,,the1 by  ,,capt4 ,h4 ,g4 ,,lyons4     
#aijf4 #daa pp41 #ad maps1 #cd          

illustrations4 ,price1  #djj milliemes4 
,,turco-,,egyptian ,,boundary ,,between 
,,the ,,vilayet ,,of ,,the ,,hejaz      
,,and ,,the ,,peninsula ,,of            
,,sinai--,,the ,,delimitation ,,of      
,,the1 by  ,e4 ,b4 ,h4 ,,wade1 together 
with additions by ,b4 ,f4 ,e4 ,,keeling 
and  ,j4 ,i4 ,,craig4 #aijf4 7,survey   
,department ,paper1 ,no4 #d74 #hi pp41  
#b  maps4 ,price1 #aej milliemes4 ,see  
also ,geology4                          
,geology4      ,,abu ,,roash1 ,,near    
,,the ,,pyramids ,,of                   
,,giza--,,cretaceous ,,region ,,of1  by 
,h4 ,j4 ,l4 ,,beadnell4 #aijb4 #dh pp41 
#b maps1 #ai illust4 ,price1  #bjj      
milliemes4    ,,arsinoitherium ,,zitteli
 7,beadnell71 ,,from ,,the ,,upper      
,,eocene ,,strata  ,,of                 
,,egypt--,,preliminary ,,note ,,on1 by  
,h4 ,j4 ,l4 ,,beadnell4 #aijb4 #d pp41  
#f illustrations4 ,price1 #ej milliemes4
    ,,aswan 7,,first7 ,,cataract ,,of   
,,the ,,nile--,,description ,,of1 by    
,,dr4 ,,ball4 #aijg4 #aba pp41 #e maps1 

#bh illustrations4 ,price1 #bjj         
milliemes4    ,,baharia ,,oasis1 ,,its  
,,topography ,,and ,,geology1 by ,,dr4  
,,ball and  ,h4 ,j4 ,l4 ,,beadnell4     
#aijc4 #hd pp41 #h maps1 #b illust4     
,price1 #bjj  milliemes4    ,,blackened 
,,rocks ,,of ,,the ,,nile ,,cataracts   
,,and ,,of ,,the ,,egyptian ,,deserts1  
by ,a4 ,,lucas4 #aije4 #eh pp4 ,price1  
#ajj milliemes4    ,,building ,,stones  
,,in ,,egypt--,,disintegration ,,of1 by 
,a4 ,,lucas4 #aijb4 #ag  pp4 ,price1 #ge
 milliemes4    ,,building ,,stones ,,of 
,,cairo ,,neighbourhood ,,and ,,upper   
,,egypt1 by  ,,dr4 ,,hume4 #aiji4 #ib   
pp41 #i illustrations4 ,price1 #aej     
milliemes4 ,survey  ,department ,paper1 
,no4 #af4    ,,cairo ,,and              
,,suez--,,topography ,,and ,,geology    
,,of ,,the ,,district ,,between1  by ,t4
 ,,barron4 #aijg4 #acc pp41 #b maps1 #ad
 illustrations4 ,price1  #bjj milliemes4
    ,,catalogue ,,of ,,the ,,geological 
,,museum1 ,,cairo1 by ,,dr4 ,,hume4     
#aije4 #cg  pp4 ,price1 #be milliemes4  

,,dakhla ,,oasis1 ,,its ,,topography    
,,and ,,geology1 by  ,h4 ,j4 ,l4        
,,beadnell4 #aija4 #ajg pp41 #i maps1 #g
 illustrations4 ,price1  #bjj milliemes4
    ,,eastern ,,desert ,,of ,,egypt1    
,,central ,,portion--,,topography ,,and 
,,geology ,,of1  by ,t4 ,,barron and    
,,dr4 ,,hume4 #aijb4 #cca pp41 #aj maps1
 #cj illust4 ,price1  #djj milliemes4   
,,eastern ,,desert ,,of ,,egypt1        
,,between ,,latitudes #bb ,,and #be     
,n4--,,preliminary ,,report ,,on        
,,geology ,,of1 by ,,dr4 ,,hume4 #aijg4 
#gb pp41 #d  maps1 #e illust4 ,price1   
#aej milliemes4 ,survey ,department     
,paper1 ,no4 #a4    ,,farafra ,,oasis1  
,,its ,,topography ,,and ,,geology1 by  
,h4 ,j4 ,l4 ,,beadnell4 #aija4 #ci pp41 
#h maps4 ,price1 #aej milliemes4        
,,fayum ,,province ,,of                 
,,egypt--,,topography ,,and ,,geology   
,,of1 by  ,h4 ,j4 ,l4 ,,beadnell4 #aije4
 #aja pp41 #b maps1 #bb illustrations4  
,price1  #cjj milliemes4    ,,for,,ts   
,p,,trifi,,es ,,des ,d,,serts ,,de      

,l',,egypte--,,note ,,sur ,l',,ge       
,,des1 par ,m4 ,r4 ,,fourteau4 #ahih4   
,french4 #h pp4 7,out of print74        
,,iron ,,ores ,,in                      
,,egypt--,,distribution ,,of1 by ,,dr4  
,,hume4 #aiji4 #af pp41  #a map4 ,price1
 #ej milliemes4 ,survey ,department     
,paper1 ,no4 #bj4    ,,jebel ,,garra    
,,and ,,the ,,oasis ,,of                
,,kurkur--,,topographical ,,and         
,,geological  ,,results ,,of ,a         
,,reconnaissance-,,survey ,,of1 by ,,dr4
 ,,ball4 #aijb4 #dj pp41  #b maps1 #e   
illustrations4 ,price #aej milliemes4   
,,kharga ,,oasis1 ,,its ,,topography    
,,and ,,geology1 by ,,dr4 ,,ball4 #aijj4
 #aaf pp41  #ai maps1 #af illustrations4
 ,price1 #bej milliemes4                
,,mammals--,,preliminary ,,note ,,on    
,,some ,,new--,,from ,,the ,,upper      
,,eocene ,,of ,,the  ,,fayum1 ,,egypt1  
by ,c4 ,w4 ,,andrews and ,h4 ,j4 ,l4    
,,beadnell4 #aijb4 #i pp41  #d          
illustrations4 ,price1 #ajj milliemes4  
,p,,trole ,,de ,,la ,,mer               

,,rouge--,,rapport ,,sur ,,les          
,,recherches ,,du1 par  ,j4 ,,barois4   
#ahhe4 ,french4 #af pp41 #a map1 #aj    
illustrations4 ,price1  #ajj milliemes4 
,,petroleum ,,districts ,,situated ,,on 
,,the ,,red ,,sea ,,coast--,,report     
,,on1  by ,,col4 ,c4 ,e4 ,,stewart4     
#ahhh4 #be pp4 ,price1 #ajj milliemes4  
,,petroleum ,,industry ,,at             
,,baku--,,sketch ,,report ,,of1 by  ,j4 
,h4 ,,trevithick4 ,may1 #ahhf4 #bb pp4  
,price1 #ajj milliemes4    ,,phosphate  
,,deposits ,,of ,,egypt1 by ,,survey    
,,department1 #bnd edition  #aije4 #ce  
pp41 #c maps4 ,price1 #ej milliemes4    
,,sinai ,,peninsula 7,,south-,,eastern  
,,portion7--,,topography ,,and ,,geology
  ,,of1 by ,,dr4 ,,hume4 #aijf4 #bhj    
pp41 #e maps1 #bc illustrations4 ,price1
  #cjj milliemes4    ,,sinai ,,peninsula
 7,,western ,,portion7--,,topography    
,,and ,,geology ,,of1  by ,t4 ,,barron4 
#aijg4 #bda pp41 #b maps1 #ac           
illustrations4 ,price1  #cjj milliemes4 
,,soil ,,and ,,water ,,of ,,the ,,fayum 

,,province--,,preliminary               
,,investigation ,,of1  by ,a4 ,,lucas4  
#aijb4 #ag pp4 ,price1 #ge milliemes4   
,,soil ,,and ,,water ,,of ,,the ,,wadi  
,,tumilat ,,lands ,,under ,,reclamation1
 by  ,a4 ,,lucas4 #aijc4 #bf pp41 #a    
map1 #e illustrations4 ,price1 #ajj     
milliemes4    ,,subsoil ,,water ,,in    
,,lower ,,egypt--,,preliminary ,,note   
,,on ,,the1 by  ,h4 ,t4 ,,ferrar1       
,m4,a41 ,f4,g4,s4 #aiaj4 #af pp41 #c    
illustrations4 ,price1  #ej milliemes4  
,,the ,,movements ,,of ,,the ,,subsoil  
,,water ,,in ,,upper ,,egypt1 by ,h4 ,t4
 ,,ferrar1  ,m4,a41 ,f4,g4,s4 ,survey   
,department ,paper1 ,no4 #ai4 ,english4 
#gd pp41  #cb illustrations and #af     
maps4 ,price1 #aej milliemes4           
,,tertiary ,,vertebrata ,,of ,,the      
,,fayum1 ,,egypt--,,descriptive         
,,catalogue ,,of1  by ,c4 ,w4 ,,andrews4
 #aijf4 #cai pp41 #abd illustrations4   
,,tortoise--,,land--,,from ,,the ,,upper
 ,,eocene ,,of ,,the ,,fayum1           
,,egypt--,,preliminary ,,notice ,,of1 by

 ,c4 ,w4 ,,andrews and  ,h4 ,j4 ,l4     
,,beadnell4 #aijc4 #aa pp41 #c          
illustrations4 ,price1 #ej milliemes4   
,meteorology4      ,,daily ,,weather    
,,report4--,issued daily by the ,survey 
,department4 ,contains the readings     
taken at #bi stations in ,egypt and  the
 ,sudan1 and five stations in southern  
,europe1 with a map showing  the        
distribution of pressure4 ,post free1   
#bjj milliemes quarterly1  including    
short monthly summary4    ,,summary ,,of
 ,,the ,,weather ,,in ,,egypt1 ,,sudan1 
,,and ,,the ,,surrounding  ,,region4    
,monthly4--,contains a brief report on  
the weather for  the month1 with maps   
showing the pressure-distribution for   
each  day4 ,price1 post free1 #cjj      
milliemes per annum4    ,,annual        
,,meteorological ,,report4--,contains   
all the meteorological  readings made   
during the year in ,egypt and the       
,sudan4 ,also the  readings of the      
various ,nile gauges4      ,years       
#ahih-ahii1 #aijj1 #aija1 #aijb1        

#aijc                                   
,price1 #bej mill4 each4      ,years    
#aijd1 #aije 7in two parts3    ,part ,i 
containing the readings    taken at     
,helwan ,observatory1 ,part    ,,ii     
containing the readings for the    rest 
of ,egypt and the ,sudan7               
,price1 #ajj mill4 each part4      ,year
 #aijf 7,part ,i1 ,helwan7              
,price1 #ajj mill4      ,year #aijf     
7,part ,,ii1 ,rest of ,egypt    and the 
,sudan7                                 
,price1 #aej mill4      ,year #aijg     
7,parts ,i and ,,ii7                    
,price1 #aej mill4 each part4      ,year
 #aijh 7,parts ,i and ,,ii7             
,price1 #aej mill4 each part4           
,nile ,flood4      ,,measurement ,,of   
,,the ,,volumes ,,discharged ,,by ,,the 
,,nile ,,during #aije  ,,and #aijf1 by  
,e4 ,m4 ,,dowson2 ,,with ,a ,,note ,,on 
,,rating ,,formul ,,for                 
,,current-,,meters1 by ,j4 ,i4 ,,craig4 
7,survey ,department ,paper1 ,no4 #aa74 
#hb  pp41 #f illustrations4 ,price1 #ajj

 milliemes4    ,,rains ,,of ,,the ,,nile
 ,,basin3--    ,in #aijd1 by ,,capt4 ,h4
 ,g4 ,,lyons4 #be pp41 #a map1 #e       
illustrations4 ,price1  #ej milliemes4  
,in #aije1 by ,,capt4 ,h4 ,g4 ,,lyons4  
#dj pp41 #d maps1 #e illustrations4     
,price1  #ej milliemes4    ,,rains ,,of 
,,the ,,nile ,,basin ,,and ,,the ,,nile 
,,flood3--    ,in #aijf1 by ,,capt4 ,h4 
,g4 ,,lyons4 7,survey ,department       
,paper1 ,no4 #b74 #gj  pp41 #e maps1 #aa
 illustrations4 ,price1 #ajj milliemes4 
,in #aijg1 by ,,capt4 ,h4 ,g4 ,,lyons4  
7,survey ,department ,paper1 ,no4 #i74  
#ej  pp41 #a map1 #aa illustrations4    
,price1 #ajj milliemes4    ,in #aijh1 by
 ,,capt4 ,h4 ,g4 ,,lyons4 7,survey      
,department ,paper1 ,no4 #ad74 #fi  pp41
 #a map1 #h illustrations4 ,price1 #ajj 
milliemes4    ,in #aiji1 by ,j4 ,i4     
,,craig4 7,survey ,department ,paper1   
,no4 #ag74 #ee pp41  #a map1 #h         
illustrations4 ,price1 #ajj milliemes4  
,special ,papers on ,meteorology4       
,,atmospheric                           

,,electricity--,,discussion ,,of ,,the  
,,observations  ,,on--,,at ,,helwan     
,,observatory1 ,,from ,,march #aijf ,,to
 ,,february #aijh1 by  ,h4 ,e4 ,,hurst4 
7,survey ,department ,paper1 ,no4 #aj74 
#fe pp41 #b maps1  #h illustrations4    
,price1 #ajj milliemes4    ,,climate    
,,of ,,abbassia1 ,,near ,,cairo1 by ,b4 
,f4 ,e4 ,,keeling4 7,survey  ,department
 ,paper1 ,no4 #c74 #aijg4 #fa pp41 #a   
map1 #g illustrations4 ,price1  #ajj    
milliemes4    ,,evaporation ,,in ,,egypt
 ,,and ,,the ,,sudan1 by ,b4 ,f4 ,e4    
,,keeling4 7,survey  ,department ,paper1
 ,no4 #ae74 #aiji4 #bi pp41 #a          
illustration4 ,price1  #ajj milliemes4  
,,platinum-,,resistance                 
,,thermometers--,,report ,,on ,,the     
,,use ,,of--,,in  ,,determining ,,the   
,,temperature ,,of ,,the ,,air ,,at     
,,the ,,helwan ,,observatory1  by ,e4   
,b4 ,h4 ,,wade4 #aije4 #bj pp41 #e      
illustrations4 ,price1 #ej milliemes4   
,surveying4      ,,altitudes--,,the     
,,determination ,,of--,,by ,,levelling1 

by  ,e4 ,m4 ,,dowson4 7,technical       
,lecture74 #aijh4 #bc pp41 #f           
illustrations4 ,price1 #ej milliemes4   
,,cadastral ,,survey ,,of ,,egypt1      
#ahib-aijg1 by ,,capt4 ,h4 ,g4 ,,lyons4 
#aijh4 #dba  pp41 #cj maps1 #af         
illustrations4 ,price1 #djj milliemes4  
,,cadastral ,,survey ,,of               
,,egypt--,,comparison ,,of--,,with      
,,those ,,of  ,,some ,,european         
,,countries1 by ,,capt4 ,h4 ,g4 ,,lyons4
 7,technical  ,lecture74 #aiji4 #bd pp41
 #h maps4 ,price1 #ej milliemes4        
,,errors ,,of ,,observation1 by ,t4 ,l4 
,,bennett4 7,technical ,lecture74 #aijh4
 #bg  pp41 #c illustrations4 ,price1 #ej
 milliemes4                             
,,longitude--,,determination ,,of1 by   
,e4 ,b4 ,h4 ,,wade4 7,technical         
,lecture7  #aijh4 #ci pp41 #b maps1 #a  
illustration4 ,price1 #ej milliemes4    
,,longitudes--,a ,,field ,,method ,,of  
,,determining--,,by ,,observations ,,of 
,,the  ,,moon1 by ,e4 ,b4 ,h4 ,,wade4   
7,survey ,department ,paper1 ,no4 #e74  

#aijg4 #dg  pp41 #i illustrations4      
,price1 #ajj milliemes4                 
,,map-,,projections1 by ,j4 ,i4 ,,craig4
 7,technical ,lecture74 #aiji4 #be pp41 
#a map1 #be illustrations4 ,price1 #ej  
milliemes4    ,,map-,,projections--,,the
 ,,theory ,,of--,,with ,,special        
,,reference ,,to ,,the  ,,projections   
,,used ,,in ,,the ,,survey ,,department1
 by ,j4 ,i4 ,,craig4 ,f4,r4,s4,e41      
7,survey ,department ,paper1 ,no4 #ac74 
#aiaj4 #gg pp41 illustrated4 ,price1    
#bjj milliemes4    ,,relief ,,on        
,,maps--,,the ,,representation ,,of1 by 
,,capt4 ,h4 ,g4 ,,lyons4 7,technical    
,lecture74 #aiji4 #ai pp41 #e maps4     
,price1  #ej milliemes4                 
,terrestrial ,magnetism4      ,,magnetic
 ,,observations ,,in ,,egypt1           
#ahie-aije1 ,,with ,a ,,summary ,,of    
,,previous  ,,magnetic ,,work ,,in      
,,northern ,,africa1 by ,b4 ,f4 ,e4     
,,keeling4 7,survey  ,department ,paper1
 ,no4 #f74 #aijg4 #fe pp41 #d maps4     
,price1 #ajj milliemes4    ,,magnetic   

,,observations ,,made ,,from ,,april    
,,to ,,december1 #aijg1 ,,at ,,helwan   
,,observatory4 #h pp4 ,price1 #be       
milliemes4    ,,magnetic ,,observations 
,,made ,,during #aijh ,,at ,,helwan     
,,observatory4 #aa  pp4 ,price1 #be     
milliemes4    ,,the ,,same ,,for #aiji4 
#aa pp4 ,price1 #ej milliemes4          
,,standardization ,,of ,,the ,,magnetic 
,,instruments ,,at ,,helwan             
,,observatory  ,,during #aijg1 by ,h4   
,e4 ,,hurst4 7,survey ,department       
,paper1  ,no4 #h74 #aijh4 #de pp41 #d   
illustrations4 ,price1 #ajj milliemes4  
,miscellaneous4      ,,annual ,,reports 
,,on ,,the ,,work ,,of ,,the ,,survey   
,,department1 by the                    
,director-,general1 as follows3 #aije1  
#abj milliemes2 #aijf1 #aijg1  #aijh and
 #aiji1 #ajj milliemes each4            
,,chemistry ,,of ,,the ,,river ,,nile1  
by ,a4 ,,lucas1 #aijh4 7,survey         
,department  ,paper1 ,no4 #g74 #gh pp41 
#a map1 #a illustration4 ,price1 #aej   
milliemes4    ,,collection ,,of         

,,statistics ,,of ,,the ,,areas         
,,planted ,,in ,,cotton ,,in #aiji1  by 
,e4 ,m4 ,,dowson and ,j4 ,i4 ,,craig4   
#aiji4 ,english or ,arabic4 #gg pp41  #h
 illustrations4 ,price1 #aej milliemes  
each4    ,,collection ,,of ,,statistics 
,,of ,,the ,,areas ,,planted ,,in       
,,cotton ,,in  #aiaj4 #aiaj4 ,english or
 ,arabic4 ,price1 #ej milliemes each4   
,,preservative ,,materials ,,used ,,by  
,,the ,,ancient ,,egyptians ,,in        
,,embalming1  by ,a4 ,,lucas1 ,f4,i4,c4 
7,survey ,department ,paper1 ,no4 #ab74 
#aiaa4 #ei  pp4 ,price1 #ajj milliemes4 
99 99 99 99 99      ,footnote3  #a  #ige
 milliemes2  #a  #bjj milliemes2 ,mk4 #a
  #dh  milliemes2 ,fr4 #a  #ch          
milliemes4                              
99 99 99 99 99                          
,imp4 ,nat4 #dcbc-aiaj-bej br4          
99 99 99 99 99