566 
NATURE 
[April 13, 1882 
Within this floor is sunken the great inner gorge, 3000 feet deep, 
with nearly vertical walls. The width of the inner gorge is 
about the same as the depth, or 3000 to 3500 feet. The strata 
exposed in this section are 4500 feet of Carboniferous (the entire 
local series), and 500 or 600 feet of Lower Silurian or Primor- 
dial. The speaker then indicated the salient features of the 
topography and stratigraphy of the country in the vicinity of the 
chasm. It is for the most part a desert plain, surfaced by the 
summit beds of the Carboniferous, with low mounds or flats 
consisting of remnants of the Permian, and occasionally a small 
remnant of the Lower Trias. Forty miles north of the chasm 
is found the main Permian mass lying as a higher bench or 
terrace terminated southwardly by a cliff. Proceeding northward, 
the Trias, the Jurassic, the Cretaceous, and the Lower Eocene 
systems are successively encountered, each at intervals of five to 
ten miles. Each of these formations is likewise terminated south- 
wardly by a great cliff, and the whole series, from the Per- 
mian to the Eocene inclusive, constitute a stairway leading 
up to the high plateaux of Utah. Capt. Dutton stated 
that conclusive evidence has been found that these terraced 
formations, thus abruptly terminated, once extended southward 
across the Grand Cafion and far into Central Arizona, but have 
been denuded down to the summit of the Carboniferous, The 
total thickness of beds removed was a little over 10,000 feet, and 
the eroded area was from 13,000 to 15,000 square miles, This area 
is called by him the Grand Cajfion district. The erosion began 
about the middle of Eocene time, and has continued uninter- 
ruptedly to the present. The cutting of the Grand Cafion is 
merely the closing episode of a much greater work. The excava- 
tion of the present cafion is a comparatively recent geological 
event, and Capt. Dutton is of the opinion that its origin does not 
antedate the Pliocene period. He then explained some of the more 
important considerations and conditions upon which the cutting 
of cafions depends, and showed the natural mechanical process of 
creating and maintaining the singularly beautiful and archi- 
tectural profiles of the cliffs, and how their wonderfully constant 
outlines are preserved. He then entertained his audience by a 
graphic and enthusiastic description of the phenomenal scenery 
revealed in the wider and deeper portions of the chasm. 
THE geology of Spain being yet very imperfectly known, we 
are glad to find in a recent number of the Bolefin of the 
Geographical Society of Madrid the continuation of Don Juan 
Vilanova’s paper on the geological survey of the province of 
Valencia, being a description of the Tertiary formation of the 
province. This formation consists of conglomerates and clays 
covered with marls, sandstones, grits, and gypsum, with beds of | 
lignite and peat. The surface is undulated, forming low hills 
with gentle slopes, but intersected with deep ravines, or barran- 
cos, or terrace-like, with deep ravines, along which streams flow 
in cascades during the rainy season. Wide lacustrian basins at 
Bicorp, which were considered by Verneuil as Cretaceous, belong 
also to this formation. 
THE Jubilee Meeting of the British Medical Association will 
be held at Worcester, on August 8-11, The president-elect is 
Dr. William Strange, senior physician to the General Infirmary, 
Worcester. 
PROF, HAECKEL is giving some account of his recent visit to 
Ceylon and India in the Deutsche Rundschau. 
WE read in the ‘‘ Diario de Manila” that a German ethno- 
logist, Dr. Schadenberg, of Breslau, has now resided for some 
time amid the savage tribes in Sibotam, at the foot of the Vol- 
cano of Apo, for the purpose of studying the ethnography of 
the tribes of Atas, Bagobos, Manobos, Mandayas, Tagacaolos, 
Vilanes, Samales, Sanguiles, Moros, and Guiangas. All these 
races differ materially in language, religious customs, attire, and 
habits, so that Dr. Schadenberg has certainly selected a rich 
field of study. 
In a brochure published by Messrs, Sampson Low and Co., 
Col. Burnaby has given an interesting narrative of his recent 
balloon trip across the Channel. 
THE additions to the Zoological Society’s Gardens during the 
past week include a Black-eared Marmoset (Hafale fenicillata) 
from South-East Brazil, presented by Mrs. Davidson; a Ring- 
tailed Lemur (Lemur catfa g) from Madagascar, presented by 
Dr. J. Lea, M.R.C.S. ; two Grey-backed White-eyes (Zosterops 
dorsalis) from Australia, presented by Mr. J. Abrahams; a 
Jardine’s Parrot (Paocephalus gulielmi) from West Africa, pre- 
sented by Capt. H. Hope Keighley, 2nd W.I. Regt. ; three 
Zebra Waxbills (Zstrelda subflava), a Shining Weaver Bird 
(Aypochera mitens) from Africa, two Amaduvade Finches 
(Zstrelda amandava) from India, a Crimson-eared Waxbill 
(Zstrelda phenicotis) from West Africa, presented by Mrs. 
Beauclerk ; a Common Buzzard (Buteo vulgaris), British, pre- 
sented by Mr. J. C. S. Rocke ; a Common Partridge (Perdix 
cinerea 3), British, presented by Mr. H. T. Bowes; a Long- 
tailed Copsychus (Cofsychus saularis) from India, deposited ; a 
Mantchurian Crossoptilon (Crossoptilon mantchuricum g) from 
North China, two Japanese Pheasants (Phasianus versicolor & ?) 
from Japan, an Amherst Pheasant (7haumalea amherstig 2), a 
Gold Pheasant (7haumal-a picta 2?) from China, a Lineated 
Pheasant (Zzplocamus lineatus &) from Tenasserim, two Black- 
backed Kaleeges (Zuplscamus melanotus 6 9) from Sikkim, 
two White-crested Kaleeges (Zuplocamus albo-cristatus $2) 
from North-West Himalayas, two Hasting’s Horned Tragopans 
(Ceriornis hastingii 2) from North India, purchased ; a Rifle 
Bird (Pulorhis paradisea 6) from Australia, received on ap- 
proval ; a Sambur Deer (Cervus aristoteles 2), a Gaimard’s Rat 
Kangaroo (Aypsifrymnus gaimarat), born in the Gardens, 
OUR ASTRONOMICAL COLUMN 
A SYSTEMATIC SEARCH FOR COMETS.—The necessity of a 
more rigorous and systematic examination of the heavens with 
the view to the early discovery of telescopic comets has been 
somewhat forcibly exemplified of late years, and it is satisfactory 
to learn that American observers are taking the initiative vigo- 
rously in this direction. A partial arrangement for regular 
sweeping has been made, and is detailed ina circular issued from 
the office of the Sc¢ence Odserver, in which also further coopera- 
tion is invited, and it is to be hoped that amateurs here with the 
necessary instruments, and time at command, will actively 
second the efforts that are being made in the United States, to 
further our knowledge of the-e, as yet, in a cosmical sense at 
least, problematical bodies. Mr. W. F. Deuning, of Bristol, 
after proving his extraordinary patience and perseverance in the 
observation of meteors, and who has done excellent work in that 
class of observation, has for some months instituted a search for 
comets in such quarters of thesky as his position best commanded, 
and has made, as we know, a most notable beginning by the 
detection of the comet of short period, which astronomers will 
recognise in future as ‘‘Denning’s comet.” He has kindly 
| afforded us an opportunity of perusing a letter addressed to him 
by Mr. J. Ritchie, jun., of Boston, U.S., from which we may 
be pardoned for making the following extract :—‘‘ We wish it 
understood that although from the circumstances of the organisa- 
tion, the majority of observers are here in this country, still we 
do not wish to make anything exclusive or national about it, and 
are simply after the most scientific ways of doing certain things, 
and are ready to receive that advice which the experience of 
others renders them competent to give.” Mr. Denning has 
found a coadjutor to divide with him the examination of the 
eastern sky in the morning hours, and there should be little diffi- 
culty in arranging for other amateurs here to take part in an 
evening search. Two or more observers in the other hemisphere 
will be needed to complete the regular scrutiny of the whole sky, 
and we do not anticipate that the scheme will be rendered im- 
perfect for want of them. 
It would be an easy matter to cite a number of cases where 
the earlier detection of comets would have materially aided our 
knowledge of their motions in space, and probably of their 
gradual development in approaching the sun. We may refer to. 
