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Sept. 9, 1886] 
of Sinafis arvensis, L., among the flax seed testifies to the 
presence of this weed in the flax crops of the days of Pharaoh, 
as of our own time. There is not a single field of flax in Egypt 
where this charlock does not abound, and often in such quantity 
that its yellow flowers, just before the flax comes into bloom, 
present the appearance of a crop of mustard. The charlock is 
Sinapis arvensis, L., var. Allionii, Jacq., and is distinguished 
from the ordinary form by its globular and inflated silicules, 
which are as characteristically present in the ancient specimens 
from the tombs as in the living plants. Azmex dentatus, L., 
the dock of the Egyptian fields of to-day, has been found in 
graves of the Greek period at Dra-Abu-Negga. 
It is difficult without the actual inspection of the specimens of 
plants employed as garlands, which have been prepared by Dr. 
Schweinfurth, to realise the wonderful condition of preservation 
in which they are. The colour of the petals of Pupaver Rheas, 
L., and the occasional presence of the dark patch at their bases 
present the same peculiarities as are still found in this species 
growing in Egyptian fields. The petals of the larkspur 
(Delphinium ortentale, Gay) not only retain their reddish-violet 
colour, but present the peculiar markings which are still found 
in the living plant. A garland composed of wild celery (Apzzm 
graveolens, L.) and small flowers of the blue lotus (Wymphea 
cerulea, Sav.), fastened together by fibres of papyrus, was found 
on a mummy of the twentieth dynasty, about three thousand 
years old. ‘he leaves, flowers, and fruits of the wild celery 
have been examined with the greatest care by Dr. Schweinfurth, 
who has demonstrated in the clearest manner their absolute 
identity with the indigenous form of this species now abundant 
in moist places in Egypt. The same may be said of the other 
plants used for garlands, including two species of lichens. 
It appears to have been a practice to lay out the dead bodies 
ona bier of fresh branches, and these were inclosed within the 
linen wrappings which enveloped the mummy. In this way 
there have been preserved branches of considerable size of Ficus 
Sycomorus, 1, Olea europea, L., Mimusops Schimperi, W., and 
Tamarix nilotica, Ehrb, The Mimusops is of frequent occur- 
rence in the mural decorations of the ancient temples ; its fruit 
had been detected amongst the offerings to the dead, and de- 
tached leaves had been found made up into garlands, but the 
discovery of branches with their leaves still attached, and in 
on: case with the fruit adhering, has established that this plant 
is the Abyssinian species to which Schimper’s name has been 
given, and which is characterised by the long and slender petiole 
of the leaf. 
_ Innone of the species, except the vine to which I have re- 
rerred, which Dr. Schweinfurth has discovered, and of which he 
has made a careful study, has he been able to detect any pecu- 
liarities in the living plants which are absent in those obtained 
from the tombs. 
Before passing from these Egyptian plants I would draw 
attention to the quality of the cereals. They are good spect- 
mens of the cereals still cultivated. This observation is true 
also of the cultivated grains which I have examined, belonging 
to prehistoric times. ‘Che wheat found in the purely British 
portion of the ancient village explored by General Pitt-Rivers is 
equal to the average of wheat cultivated at the present day. 
This is the more remarkable, because the two samples from the 
later Romano-British period obtained by General Pitt-Rivers are 
very much smaller, though they are not unlike the small hard 
grains of wheat still cultivated on thin chalk soils. The wheat 
froin lake-dwellings in Switzerland, for which I am indebted to 
Mr. J. T. Lee, F'.G.S., are fair samples. My colleague, Mr. 
W. Fawcett, has recently brought me, from America, grains of 
maize from the prehistoric mounds in the valley of the Missis- 
sippi, and from the tombs of the Incas of Peru, which represent 
also fair samples of this great food substance of the New World. 
The early peoples of both worlds had then under cultivation 
productive varieties of these important food-plants, and it is 
remarkable that in our own country, with all the appliances of 
scientific cultivation and intelligent farming, we have not been 
able to appreciably surpass the grains which were harvested by 
our rude ancestors of 2009 years ago. 
In taking a further step into the past, and tracing the remains 
of existing species of plants preserved in the strata of the earth’s 
crust, we must necessarily leave behind all certain chronology. 
Without an intelligent observer and recorder there can be no 
definite determination of time. We can only speculate as to the 
period required for effeeting the changes represented by the 
various deposits. 
NATURE 
453 
The peat-bogs are composed entirely of plant-remains belong- 
ing to the floras existing in the regions where they occur. They 
are mainly surface-accumulations still being formed and going 
back to an unknown antiquity. They are subsequent to the 
last changes in the surface of the country, and represent the 
physical conditions still prevailing. 
The period of great cold during which Arctic ice extended far 
into temperate regions was not favourable to vegetable life. 
But in some localities we have stratified clays with plant- 
remains later than the Glacial epoch, yet indicating that the 
great cold had not then entirely disappeared. In the lacustrine 
beds at Holderness is found a small birch (Betula nana, L.), 
now limited in Great Britain to some of the mountains of Scot- 
land, but found in the Arctic regions of the Old and New World 
and in Alpine districts in Europe, and with it Prous Padus, 
L., Quercus Robur, L., Corylus Aveilana, L., Alnus glutinosa, 
L., and Pinus sylvestris, L. In the white clay beds at Bovey 
Tracey of the same age there occur the leaves of Arctostaphylos 
Qva-Ursi, L., three species of willow, viz. Salix cinerea, L, S. 
myrtilloides, L., and S. polaris, Wahl., and in addition to our 
alpine Betula nana, L., the more familiar 4. alba, L. In beds 
of the same age in Sweden, Nathorst has found the leaves of 
Dryas octopetala, L., and Salix herbacea, ., this being asso- 
ciated with S. polaris, Wahl. Two of these plants have been 
lost to our flora from the change of climate that has taken place, 
viz. Salix myrtilloites, L., and S. polaris, Wahl, 5 and Betula 
nanz, L, has retreated to the mountains of Scotland. Three 
others (Dryas octopztala, L., Arctostaphylos Uva-Ursi, L., and 
Salix herbacex, L.), have withdrawn to the mountains of 
Northern England, Wales, and Scotland, while the remainder 
are still found scattered over the country. Notwithstanding the 
diverse physical conditions to which these plants have been 
subjected, the remains preserved in these beds present no cha- 
racters by which they can be distinguished from the living 
representatives of the species. 
We meet with no further materials for careful comparison 
with existing species until we get beyond the great period of 
intense cold which immediately preceded the present order of 
things. The Glacial epoch includes four periods during which 
the cold was intense, separated by intervals of somewhat higher 
temperature, which are represented by the intervening sediment- 
ary deposits. During these alterations of temperature, extensive 
changes in the configuration of the land were taking place. 
The first great upheaval occurred in the early Glacial period, 
and was followed by a considerable subsidence. A second up- 
heaval took place late in the Glacial epoch. Various estimates 
have been formed of the time required for this succession of 
climatic conditions and earth-movements. The moderate com- 
putation of Ramsay and Lyell gives to the boulder-clay of the 
first Glacial period an age of 250,000 years, estimating the time 
of the first upheaval as 200,000 years ago, while the subsidence 
took place 50,090 years later, and the second upheaval 92,000 
years ago. ; 
The sedimentary deposits later than the Pliocene strata, but 
older than the Glacial drift, indicate an increasing severity in 
the climate, which reached its height in the first Glacial period. 
At Cromer, on the Norfolk coast, the newest of these deposits 
has supplied the remains of Salix polaris, Wahl., S. cenerea, 
L., and Aypuum turgescens, Schimp. This small group of 
plants is of great interest in connection with the history of 
existing species ; their remains are preserved in such a manner 
as to permit the closest comparison with living plants. Such an 
examination shows that they differ from each other in no par- 
ticular. In the post-Glacial deposits in Sweden, Salix herbacea, 
L., is associated with S. polaris, Wahl., as I have already stated. 
These two willows are very closely related, having indeed been 
treated as the same species until Wahlenberg pointed out the 
characters which separated them when he established Salix 
polaris as a distinct species in 1812. One of the most obvious of 
the specific distinctions is the form and venation of the leaf, a 
character which is, however, easily overlooked, but when once 
detected is found to be so constant that it enables one to dis- 
tinguish without hesitation the one species from the other. The 
leaves of the two willows in the Swedish bed present all the 
peculiarities which they possess at the present day, and the 
venation and form of the leaves of S, polaris, Wahl., from the 
pre-Glacial beds of Cromer, present no approach towards the 
peculiarities of its ally S. Aerbacea, L., but exhibit them exactly 
as they appear in the living plant. This is the more noteworthy 
as the vegetative organs supply, as a rule, the least stable of the 
