The findings of paleomagnetic studies of deposits of different ages from various parts of the Soviet Union were discussed in the first group of reports. The regions covered in these studies were: the Russion Platform, the Ukraine (including the Crimean region), Armenia, the Urals, Kazakh stan, the southern part of the Siberian Platform, and the central part of the Krasnoyarsk Territory. This group also included a report on the study of secular variations using archeomagnetic methods.
A. N. Khramov and his coworkers presented the results of some new affirmative tests of making up composite key sections of rocks, using the paleomagnetic method. These tests were used to correlate the deposits laid down over vast territories.
A paleomagnetic analysis of sedimentary strata from the Upper Devonian was presented by T. I. Lin'kova. These studies indicated that rotation of the geomagnetic field took place during the Devonian, since directly and reversely magnetized rocks were found to have identical ferromagnetic compositions. The pole positions computed on the basis of these measure ments agreed well with the data of other authors.
G. I. Kruglyakova and A. N. Tret'yak reported on a series of measure ments of the remanent magnetization of rocks from the Cambrian, Ordovician, Silurian, Devonian, and Carboniferous periods; the rocks studied were found in the Ukraine. The coordinates of the poles were calculated for the corresponding epochs. Ts. G. Akopyan discussed the stratigraphical correlation and the differentiation of Cenozoic volcanogenic formations in the Armenian SSR and in the adjacent parts of the Lesser Caucasus Mountains, on the basis of paleomagnetic measurements.
V. V. Kochegura and B. Sh. Rusinov gave the results of their study of reverse magnetization in Devonian porphyrites. It is these authors' opinion that the value of Q drops exponentially with age, and that thus the Q factor can serve as a criterion for the stability of rocks. The position of the pole during the Carboniferous period, as determined by Gzhel' clays from the region around Moscow, was discussed by O. L. Andreeva. These clays turned out to be exceptionally stable, due to the presence in them of finely dispersed hematite. The vector field of the remanent magnetization was found to be very uniform (confidence circle radius of 1°).
V. F. Davydov made a study of the remanent magnetization of traprocks in the southern part of the Siberian Platform. On the basis of computed pole positions, this author related some of the traprocks to the period between the Cambrian and the Carboniferous and some to the period between the Carboniferous and the Triassic. The conclusions of the author, however, are somewhat dubious.
The results of a study of Devonian rocks from the central part of the Krasnoyarsk Territory were presented by A. Ya. Vlasov and others. In this study, which from the methodical point of view was on a very high level, the average pole position was computed for the rocks in question.
I. A. Rezanov attempted to show in his report that horizontal movements of the continents could not have taken place. The plots of polar wandering obtained on the basis of measurements of rocks from different continents do not coincide, and this fact led to the continental-drift hypothesis. Rezanov questions the latter hypothesis, however, since, in his opinion, the spread in the pole positions for different continents is the result of a systematic error, probably introduced by a reversal of the magnetization of the rocks during subsequent periods, and thus it does not constitute evidence for continental drift.
S. P. Burlatskaya and G. N. Petrova solved the problem of the recovery of the geomagnetic field in the past, on the basis of archeomagnetic studies. Samples from the city of Tbilisi covering the period from the sixteenth century to the present were measured. As a result of these studies, the first Soviet curves of the change in direction (orientation) of the geomagnetic field, and also of the change in absolute magnitude of the field, were obtained.
These reports, particularly that of Davydov, provoked a lively discus sion. The need for a more accurate geological referencing of the samples, and thus of the measurements as well, to strata and formations was pointed out. Certain geologists criticized the conclusions of paleomag netism which lead to the hypothesis of continental drift, but this criticism was made with respect to the data of modern geology and not with respect to the correctness or incorrectness of the methods of paleomagnetism.