55° 
NATURE 
[ApriL 8, 1897 
described briefly the physical geography of th Baluchistan 
deserts, which extend along the south of the Helmund River, 
between Quetta and Persia. Taking first the plains and their 
drainage-system, he showed how the wide alluvial plains of 
Shorawak and Chagai were probably in earlier times one large 
lake. North and west of these plains, as far as Persia, lie vast 
deserts of sand, which in places were gradually encroaching 
upon and burying the mountain-ranges which rise up like islands 
in the desert. He showed how the sand had intercepted all the 
drainage from the mountains and prevented it from making its 
way, as it would otherwise have done, into the Helmund River 
and the God-i-Zirreh Lake. Turning next to the mountains, 
Captain McMahon described a well-defined line of fault, which 
he traced for a distance of about 120 miles from north of 
Chaman, along the Khwaja Amran and Sarlat mountain-ranges 
to Nushki. East of this fault all the rocks appeared to be 
sedimentary ; while those to the west were all, with few 
exceptions, volcanic and igneous. The mountain-ranges in the 
desert described appeared to be all volcanic, and reference was 
made to the Koh-i-Taftan, 12,600 feet high, lying south-west of 
them, which is still an active volcano. The curious, grotesquely- 
shaped peaks of the Koh-i-Sultan range weré then briefly 
described, and especially that named Neza-i-Sultan—a gigantic 
natural pillar of volcanic agglomerate many hundreds of feet 
high. After thus describing the general character of the country, 
Captain McMahon pointed out the very remarkable force and 
activity with which certain natural agents were at present at 
work there—namely, water, wind, sand, and extremes of heat 
and cold. In the second part of the paper General McMahon 
described the microscopical characters of the rocks, which 
consist of lavas, ashes, pumice, igneous intrusive, and sedimen- 
tary rocks. Inthe discussion which followed, the President 
remarked, concerning the corrosion of basic minerals by silica, 
that silica might be truly a corrosive mineral, but hitherto the 
idea had been that the basic mineral had decomposed 77 sz¢z, 
and that the silica had filled up the hollows and cracks resulting 
from this decomposition. Mr. Griesbach considered the paper 
a valuable contribution to our knowledge of Baluchistan. But, 
having spent some years in that part of Asia himself, he wished 
to point out that there is abundant evidence to show that the 
Pliocene deposits which are seen in Shorawak and the neigh- 
bouring Registan have not been laid down in a lake-basin, but 
are chiefly of a fluviatile nature. Dr. Blanford referred to the 
great prevalence of Tertiary and Cretaceous rocks throughout 
the wide area extending from the Indus to Mesopotamia. The 
volcanic rocks of Eastern Baluchistan, like the Deccan traps of 
India, appear to be of Cretaceous and Lower Eocene age ; 
but the igneous formations near the Baluchistan and Persian 
frontier must be, in part at all events, of far more recent origin, 
some of the cones of loose materials seen by the speaker between 
Bampur and Bam, having undergone no change through 
denudation. The Rev. Edwin Hill said the pinnacle shown 
resembled a magnified earth pillar. Was the water which dis- 
appeared in the sand ultimately evaporated? Prof. Milne made 
special reference to the fault which Captain McMahon had 
described, and compared it with a fault which in 1891 had been 
formed in Japan. Mr. Cadell said that the remarkable peaks 
described by the author, which were said to be of agglomerate, 
might be explained on the supposition that these were the necks 
of old volcanoes, the upper parts of which, together with the 
surrounding strata, had been denuded away. Prof. Judd called 
attention to the great steep-sided masses of volcanic agglomerate 
which rise up in the midst of the town of Le Puy in Central 
France, and are crowned by the cathedral and the church of 
St. Michel. These seem comparable, though of smaller 
<limensions, to the great columnar masses described by Captain 
McMahon. There is no doubt that the masses of Le Puy are 
relics left by denudation of a mass of volcanic agglomerate that 
once filled the whole valley. The reason why these masses 
have escaped removal by denudation is probably not because 
they are ‘‘ volcanic rocks,” but because these materials have 
been consolidated by the action of siliceous, calcareous, or 
chalybeate springs. Dr. H. Woodward and Mr. W. W. Watts 
also spoke, and the authors replied.—On the association of 
Sigtllaria and Glossopterés in South Africa, by A. C. Seward. 
In this paper the author described in detail several specimens of 
fossil plants submitted to him by Mr. David Draper, of 
Johannesburg. His conclusions as to the geological age of the 
plant-bearing beds differed from those arrived at by Mr. Draper 
from stratigraphical evidence ; the plants pointed to an horizon 
which may be referred to what is now termed the Permo- 
NO. 1432, VOL. 55] 
Carboniferous age. The difficulty of distinguishing between 
various forms of G/ossopterts-leaves was discussed at some length ; 
and the opinion expressed that it is practically impossible to 
separate the Indian, Australian, and African forms of G. 
Browniana, G. tndica, and others. The chief interest as regards 
the plants centred round the specimens of Szgz//aréa ; these were 
fairly well preserved impressions, and were referred to the well- 
known species, S. Brard?. In addition to various forms of 
the genus G/lossopfterzs and the specimens of Szgz//aria, the 
following plants were recorded :—WNoeggerathiopsis Hislope, 
Gangamopterts cyclopterotdes, Phyllotheca, Conztes sp., Cardio- 
carpus sp., and Sphenopterts sp.—Notes on the occurrence of 
Sigillarta, Glossopterts, and other plant-remains in the Triassic 
rocks of South Africa, by David Draper. The author gave a 
brief description of the geology of four localities, within a com- 
paratively short distance from Johannesburg, from which several 
fossil plants have recently been obtained. THe considered the 
plant-bearing beds to belong to the Lower Stormberg Series of 
Dunn, and to the horizon known as the Molteno Beds. The 
most important locality described in these notes was that of 
Vereeniging, thirty miles south of Johannesburg, where the 
author found several specimens of .Szgz//aria associated with 
Glossopterzs and other plants in iron-stained sandstones. The 
significance of this discovery of Szgz//aria was briefly discussed. 
—In the discussion on the two preceding papers, Dr. Blanford 
said that it was a source of much gratification to those who, despite 
the views of many European paleontologists, had maintained 
for years on geological evidence that the G/ossopferzs-fauna was 
Palzozoic, to find their contention confirmed by recent botanical 
discoveries. Mr. Griesbach pointed out that the fossil plants 
exhibited, showing true Carboniferous types associated with 
Glossopterts, constituted another and valuable contribution to 
our knowledge of these beds, which were known as Gondwanas 
in India; and they confirmed in a striking manner the fact, 
already accepted in India and Australia, that the lowest beds of 
this group of strata belonged to the later Carboniferous and 
Permian systems. Prof. Seeley stated that when he visited 
Aliwal North in 1889, Mr. Alfred Brown showed him many 
plants which he had obtained in white sandstone. They 
included G/ossofter?s and Lepidodendroid plants, together with 
a variety of ferns, which might be new. There was no oppor- 
tunity of visiting the locality ; but Aliwal North was near the top 
of the Karoo Series, and he though that Mr. Brown’s plants 
might be from beds yielding Zzshe/esaurus, which he would 
place above the Indwe coal. There were indications of coal 
near the base of the Karoo and in the middle, but the workable 
beds which he had seen were towards the top; although their 
flora was not the same as in the beds worked by Mr. Brown, 
which resembled the types now exhibited. He should like to 
see better evidence of the age of the beds before admitting them 
as Permo-Carboniferous, because the whole of the South 
African vertebrata of the Karoo appeared to be below the beds 
which are found near Aliwal North. The Lower Karoo com- 
prised the zone of Pareéasaurus. Then came the zone of 
Dicynodon. Above that is the zone of Prychognathus. Andat 
the top is the zone of the Theriodont reptiles, which he placed 
below the Cape coal. He had regarded all these beds as 
Permian. Mr. Stonier observed that in New South Wales 
Glossopteris was characteristic of the more important of the pro- 
ductive Coal-Measures. Feistmantel had described the Paleozoic 
plants ; but there was a difficulty, as stated by Mr. Seward, in 
distinguishing forms; and in 1894 Mr. R. Etheridge, jun., 
pointed out that the whole question of generic name, specific 
characters, &c., of Glosssopteris had become almost hopelessly 
involved. Gangamopteris and Glossopteris were associated at 
Lochinvar and Newcastle (N.S. W.). 
EDINBURGH. 
Royal Society, March 15.—Lord Kelvin in the chair.—Dr. 
James Kerr Love, Glasgow, read a paper on deaf mutism and 
its prevention. He divided deaf mutism into two classes—the 
one caused by disease, the other due to heredity or congenital 
causes. Dealing with congenital deafness, a tree was shown of 
a family, called the Ayrshire family, where about forty deaf 
mutes resulted during five generations. Dr. Love’s conclusions 
with regard to the transmission of deafness were that congenital 
deafness was hereditary either in the direct line, or it might be 
the expression of a tendency which was seen only in the 
collateral branches of a family. The anatomical lesions upon 
which deafness depended, were not one but many. The inter- 
marriage of the deaf, therefore, only perpetuated without 
