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On April 12th there was not the least doubt that, small though the differences were in the times of incidence, the peas varied greatly in the height to which they had grown and in the size of their leaves. No. 6 had come up after No. 8, and was much the worst of all. The remainder had come up within a few hours of one another, but were visibly smaller as they approached the screen. No. 8 was much smaller in every way than No. 5, and two of its five leaves were only just visible.
The leaves of No. 5 were much inferior to those of No. 2. Nos. 9
and io in the shadow of the screen had not come up, nor had Nos. 3, 4, and 7. The three latter were accordingly dug up and examined. Two of the seeds were good, and one of them was germinating. The screen was removed before sunrise on April 13th, and direct sunlight admitted to the whole of the plot by 7h. 1om. in order to see whether any of the seeds 3, 4, 7, 9, or 10 would come up. They did not do so. After the screen was removed 11 weeds appeared within the area of the shadow, whereas none had appeared there previously though there were many in other parts of the plot.
Meanwhile the peas in Plot B were teaching exactly the same lesson. Growth was in proportion to the amount of early rays the plants received, and the direct light during the rest of the day did not equalise matters. But a curious result followed from perforating the screen. The two nearest peas to it received intermittent rays
for some 6 minutes at a time between 8h. and 8h. 30m. During 9 days the leaves remained just visible above ground. There was no growth whatever. The holes were then stopped up, so that the peas remained in shadow till roh. 3om. In 7 days' time no change in colour occurred but they were only 2 m.m. and 5 m.m. high respectively. Sunrise rays were then admitted to one of them, but not to the other. The latter is dead, the former is still alive, nearly 3 months afterwards, but is barely 5 m.m. high.*
These experiments and observations appear to be worthy of consideration. The exceptional circumstances under which they were carried out must be borne in mind, but, taken in connection with the remarkable effect of sunrise rays upon the cirrus particles in the sky on March 12th, they suggest that protoplasm in the presence of water may be a medium through which the vibratory energy of the rays is conveyed to the chlorophyll-granules imbedded in it.
The lesson taught by the Kei-apple border, confirmed by the experiments with vegetables and macrocarpas, and interpreted by the cloud-phenomenon which has been described, may possibly be that the directive force lies in the rays of light, and is not entirely inherent in protoplasm. I would remind you of the discovery of protoplasm, and of its behaviour in the water-weed Vaucheria clavata. It is between the hours of 8 and 9 a.m. that new protoplasm is always put forth by a movement of rotation and forward straining (Kerner). The little ellipsoid has a polarity, and always moves with the same end forward. Its first motion is towards the light, and
* It lived till Aug. 3rd.
as it moves it turns round its longer axis invariably from east to west, or in the direction opposed to that of the earth. It behaves as if it were a little magnet actuated by currents of electricity proceeding from our kosmic system.
The critical hour of 8h. to gh. appears in a number of phenomena connected with the sun, for which we are still searching for an explanation. It is suggested that those botanists who can do so should specially examine the distribution of chlorophyll-granules on cell-walls from sunrise up to 9h. Should the result confirm the hypothesis which has been advanced to try and correlate the curious facts which have been described, we may hopefully look forward to a day when a direct connection will be proved, not only between the sun's energy, magnetic phenomena, and the running of sap, but between the sun's vibratory rays and even gravity itself.
By H. H. W. PEARSON, M.A., F.L.S.
Field observations have been carried on in 1905 and 1906 on Encephalartos Friderici-Guilielmi, Lehm., E. Altensteinii, Lehm., E. villosus, Lém., and on the open-veld” form of Stangeria, which is possibly merely a variety of S. paradoxa, Moore. The full paper (see Trans. S. A. Phil. Soc., Vol xvi., pp. 341-354) contains a discussion of the results obtained, the more important of which are here summarized.
In Encephalartos Friderici-Guilielmi and in Stangeria subterranean branching plays a part in vegetative reproduction which is not less important than in many ferns with subterranean rhizomes.
The cones are lateral in E. Friderici-Guilielmi and in E. Altensteinii, and the growth of the stem is in both cases monopodial.
E. Friderici-Guilielmi, which is subject to strong insolation, cones much more freely than either E. Altensteinii or E. villosusboth, especially the latter, shade-species.
In E. Altensteinii cones are not infrequent on plants growing in more or less open positions exposed to sunlight. As far as is known, they occur very rarely, if at all, on plants in densely-shaded situations. A few observations support a similar conclusion for E. villosus.
may be that other exceptional circumstances, such as implied in cultivation, also act as a stimulus to the production of cones.
In E. Altensteinii branched specimens seem to occur only in illuminated situations, and usually, if not always, near waterconditions which are both favourable to nutrition.
There is a distinct probability that entomophily occurs in E. villosus. The position of the cones in Stangeria, with respect to the surrounding vegetation, points to the inefficiency of the wind as a pollinating agent.
By A. W. ROGERS, M.A., F.G.S.
During the geological survey of the Hay district in 1905 a comparatively small thickness of rock near the top of the Griqua Town series was found to contain numerous boulders and pebbles shaped and scratched in the manner characteristic of stones that have received their final touches from the grinding action of moving ice. Their discovery gives evidence of the third known, but earliest, period of cold climate in South Africa, the other two being those represented by the glacial deposits in the Table Mountain and the Dwyka series.
These ancient glacial periods are extremely interesting from several points of view. First, they show that very far back in the earth's history the climate in the areas concerned was such that great accumulations of snow and ice were possible, and that consequently the world's climate of to-day may not be, on the average, hotter or colder than it was then. When the evidence concerns a period possibly older than the oldest known fossiliferous rocks of any country, its bearing on the physical conditions which have prevailed during the evolution of all the known forms of life becomes important. Then, again, the required explanation of the cold climates opens up great questions, which have yet received no probable solution. The fact that a rigorous climate would probabļy not be local in its occurrence, that it would not be confined merely to one district in this country, gives us a new means of correlating beds in distant areas.
At most places where the Griqua Town glacial rocks crop out they are very hard and dark brown or red in colour, owing to the large amount of iron oxides in them. There are several localities where the matrix is dark blue, in colour not unlike that of the Dwyka boulder beds in the south of the colony, but there is much cherty silica in it, which makes it break with a conchoidal fracture.
The dark blue rock has been found between Kort Kloof and Punt in Hay, on Good Hope in Barkly West, and at Dimoten and Monjana Mabedi, near Khosis, in the Kuruman district. The blue matrix is crowded with grains of quartz, and it also contains many small fragments of dark chert. The included pebbles and boulders are angular, subangular, or rounded, and they range up to two feet in length.
Many of them are covered on one or more sides with striæ, in the manner characteristic of glacial boulders. Some of the stones are of the “ facetted” type, that is, they have one or more nearly flat faces ; in cases where there are two or more faces they may meet along a fairly well defined edge. These faces are well striated.
There are other facetted fragments, which were found to be especially abundant at Sunnyside in Hay, though they occur at many other places, but their faces are not striated, or they have very few and short scratches on them. These fragments are invariably pieces of chert, and their form is probably the result of fracture along joints before they were enclosed in the matrix.
Throughout a large part of the rock the pebbles and boulders are distributed without any discernible arrangement, but layers of conglomerate, two or three feet thick, made up almost entirely of well
rounded pebbles, occur immediately below the unbedded rock at several localities, and thin, lenticular layers of gravelly rock were noticed in the unbedded boulder rock at Punt and Good Hope. Below the glacial horizon there is generally found a coarse ironstained grit, several feet thick.
The boulders and pebbles are chiefly made of dark chert. Some of them are nodular lumps, usually discoidal or elliptical in shape, with a distinct banding parallel to the plane in which the two longer axes of the nodule lie. These nodules are often covered on their flatter sides with the glacial scratches. Quartzite and grit pebbles are not infrequently seen, and fragments of a white-banded marble, very fine grained, occur in the blue rock at Punt, Good Hope, and Monjana Mabedi. In the red and brown outcrops these limestone fragments are represented by cavities in the matrix partly filled with iron oxides ; in the red rock the iron oxide is in the form of specular iron lining the cavity and filling it to a greater or less extent.
So far as my observations have gone, fragments of granite and other igneous rocks are not present in these beds, a striking point of difference from the other glacial boulder beds in the Colony.
The red and brown rocks certainly owe their colours to changes which have taken place subsequently to their deposition. In some of these rocks there has been an addition of iron compounds, but it is not yet known whether this access of iron is in all cases a surface phenomenon, i.e., that the iron has collected near the surface from the immediately underlying rock, or whether it has been brought from a distance. The fact that the more ferruginous and heavier varieties are particularly noticeable where the lower beds are hæmatitic jaspers, as along the west side of the Ongeluk-Witwater syncline, and the fact that the blue matrix has only been found where the lower beds are blue or brown, although there is no such change in the surface conditions as would account for the difference, make it probable that generally the increase in iron has not taken place at the present surface.
In this connection it should be remarked that the processes by which the bulk of the Griqua Town beds became converted into ferruginous jaspers were completed at the time of the formation of the Dwvka boulder beds, for large pieces of rock, which very probably came from the Griqua Town beds, have been found in the Dwyka, and in Prieska and Hay the normal Dwyka still rests upon the ferruginous jaspers.
At two places, in a sluit on the west side of the Paling ridge, and near a dried-up fountain at Monjana Mabedi, the boulder beds have been found to be more thoroughly weathered than elsewhere, and they then have a most remarkable general resemblance to both the weathered glacial beds in the Table Mountain series in Pakhuis Pass, Clanwilliam, and to the Dwvka in its weathered state. The only obvious difference in the exposures is due to the absence of other than chert, quartzite and grit boulders in the Griqua Town boulder beds.
The glacial horizon has now been found to extend from near the Orange River in Hay to about 20 miles south of Kuruman, a distance