6 
NATURE 
[SEPTEMBER 4, 1913 
inhabited only by sea-birds and seals, and the nearest 
house is on the opposite side of the island at least four 
miles away by the coast. The sea-water seemed very 
clear, of salinity 26-5, and the sandy bottom could 
be seen from the yacht anchored in five fathoms. 
Diatom patches are no doubt abundant in many 
places; probably the simple green alga encrusting the 
sand-grains is known to botanists, and I have cer- 
tainly seen the pink organism elsewhere. Probably 
other coloured patches due to micro-organisms are 
present on many beaches. It would be interesting to 
have them more thoroughly investigated—biochemic- 
ally, if possible—by someone living on the spot, and 
able to study their changes day by day. 
W. A. HeERpMaN. 
S.Y. Runa, Sound of Islay, August 27. 
Physiological Factors of Consciousness. ‘ 
Mr. Asput Majin (Nature, August 28) asks ; ‘* What 
is the true explanation of the fact that stimuli 
sufficiently strong to arouse vivid sensations in a 
subject while he is wide awake apparently fail to 
arouse any sensations at all in a state of unconscious- 
ness?”’ But is there any evidence that stimuli do not 
arouse identical sensations in the waking and the | 
sleeping states? As a medical man, I am frequently 
“rung up.’’ As far as I am able to judge, I am 
invariably awakened out of a dream. I am_ never 
dreamless. My consciousness never sleeps. 
But, in proportion to the depth of slumber, memory 
uppears to be abolished. Memory is ample in propor- 
tion as it is clear and coherent—in proportion as it 
links the present with the past and so fulfils its func- 
tion of affording a guide for the future. In dreams, 
since it is so much in abeyance, we live almost wholly 
; examine 
' between this and the Crag period? 
| we have. 
| parently 
referred to, are worked flints. Upon their testimony 
Mr. Moir, and those who agree with him, would carry 
man’s work back to the Pliocen€ period of the Suffollx 
Crag. Mr. Moir kindly allowed me to see a few of 
his specimens, and I am inclined to think that some 
of them show artificial chipping. The deposit in which 
the Piltdown skull was found is said to be early 
Pleistocene. Have we any indication of man’s worl: 
In my opinion 
I refer to the remarkable trench at Dew- 
lish, Dorset,’ which before it was excavated contained 
abundant remains of Elephas meridionalis and no 
other fossils, though Mr. Grist has found eoliths.* 
It is difficult to account for the formation of 
this peculiar trench in  challk by any natural — 
process. Mr. Clement Reid, who spent four days to 
it, tells us that ‘tthe fissure, or rather 
trough, ended abruptly without any trace of a con- 
tinuing joint. It was not a fault, for the lines of 
flint nodules corresponded on each side.’ * Mr. Reid, 
at the British Association at Cambridge, described the: 
termination of the trench as “‘apse-like.’’ It opened 
out diagonally at one end on to the steep slope of the 
side of a valley. It was 103 ft. long and 12 ft. deep. 
The width, as the photographs show, was not quite 
uniform, and Mr. Reid said that in the narrow place 
he could just get along. It is remarkable that here 
the walls approach from each side—a feature ap- 
incompatible with any natural causation. 
After the trench had been refilled, I met with a 
description and photograph of a pitfall for elephants 
‘in Africa; and that led me to believe that this trench 
was artificial, and dug out for the same purpose. 
If this view is correct, it shows that man existed im 
, Pliocene times, and was already a social being capable 
| 
in the ‘immediate present,” taking little thought of | 
ings do not then surprise us; for these do not 
then contradict stored experience. On that account, 
also, we seldom remember our dreams unless they 
occur in light slumber (half-wakefulness), or 
unless our attention is called to them immediately on 
waking while our minds are still tingling ‘with 
them. I am sure, if anyone tries the experiment 
of having himself awakened for a few occasions by 
the insistent question, “What are you dreaming 
about? "—if his attention is immediately fixed on his 
dream—he will soon be convinced that there is no 
such thing as dreamless sleep. 
By way of illustration ; I remember a terrible dream. 
An enemy had his hand on my mouth and was suf- 
focating me. I awoke to find the tail of my friend 
the cat, who had come on his morning visit, laid 
across my lips. The dreams of ill-health, and especially 
of indigestion, are usually unpleasant and sometimes 
fearful. 
I take it, then, that sensations are the stuff that 
dreams are made of. They are the same sensations 
that we feel in our waking states, but; when woven 
into our dreams, they are wrongly interpreted. 
G. ArcHDALL Rep. 
Netherby, Victoria Road, S. Southsea, 
August 209. 
The Elephant Trench at Dewlish—Was it Dug? 
THE question of the brain capacity of the Piltdown 
and other fossil skulls must be decided by anatomists ; 
but a sidelight may be thrown on the subject of the 
intelligence of early man by a consideration of the 
works of which*he was capable. The most indestruc- 
the past or the future. Absurd or improbable happen- | the express purpose of testing this questions 
of a great undertaking, for no one individual could 
have effected such a work. 
My hope is that this trench may be reopened for 
‘ It has 
/ never been bottomed except at the end where it 
| opened on the valley. 
tible of these, and consequently the most frequently / 
NO. 2288, VOL. 92] 
Elsewhere two or three feet 
remain undisturbed. If it was artificial, some indica- 
tion of the tools used might possibly be found at the 
bottom. The expense could not be great, and my 
object in writing this is to endeavour to excite such 
interest in the subject as may perhaps lead to a proper 
investigation. But a competent geologist, whose 
| verdict would carry weight, ought to undertake it. 
Graveley, Huntingdon. O. Fisuer. 
Note on the Dicynodont Vomer. 
In 1898 I directed attention to the fact that the 
paired elements in the front of the palate of lizards and 
snakes seem in all their relations to agree with the 
pair of bones in Ornithorhynchus, which afterwards 
fuse to form the dumb-bell bone, and that they cannot 
be homologous with the median unpaired vomer of 
mammals, and must have another name, and I pro- 
posed to call them prevomers. While the embryo- 
logical evidence seems conclusive, the palzeontological 
testimony has not hitherto been so satisfactory as one 
could desire. Cynodont reptiles appear to have a single 
median vomer, very like that of the mammal, and 
one specimen of Gomphognathus shows what appear 
to be a pair of elements in front.. Dicynodon appears 
to have also a single median vomer, and no paired 
elements. The Therocephalians, on the other hand, 
have a pair of large anterior elements, and apparently 
no median element. With the palzontological 
1 See paper by the writer with two photographic views, Quart. Journ. 
Geol. Soc., 1905. 
% Journ. Roy. Anthropological Institute, vol. x1., toto. 
* See ‘Geological Survey Memoirs," 1899, p. 34- 
' 
