68 GEOLOGICAL RESEARCHES IN 



The Sinian revolution seems to have begam after the deposition of the limestone, 

 and before that of the Coal measures ; at least the difference in character that is 

 visible between the beds that overlie the limestone 'on the two flanks of the anti- 

 clinal ridge in Western Hupeh, and the presence, at the bottom of the Coal measures 

 near Peking, of conglomerates, formed from porphyries that are younger than the 

 limestone, are facts that seem to favor this idea. It is not improbable that these 

 first movements determined the outlines of the principal areas of land and water, 

 and of the future coal basins. The revolution does not seem to have reached its 

 climax till after the Coal measures had been deposited, when the strata were plicated 

 and prepared for metamorphism. 



Very striking analogies are apparent between the Sinians and our own Appala- 

 chians. Both have the same trend ; both are the results of revolutions, which, 

 though they may not have been coextensive in time, were contemporaneous through 

 a long period ; and both have folded immense areas of coal-bearing strata. As the 

 elevation of the Appalachians determined the outline of Eastern America, so the 

 Sinian revolution fixed the eastern boundary of the great continent. 



We have, in this analogy, one more link in the chain of evidence toward proving 

 the subordination to harmonious laws of the causes that have produced all the varied 

 features in the configuration of our planet. 



One of the most remarkable features in the configuration of the northern 

 hemisphere, seems to me to be the number of geoclinal valleys having a nearly 

 N. E. S. W. course, that characterize it. In the extreme east of the great con- 

 tinent we find one, occupied by the sea, between the Japanese Islands and the 

 coast range of Manchuria ; between this and the Kingan mountains^ another, which 

 I have several times alluded to as the principal line of reference in treating of the 

 Sinian features; the Gobi, including the region between the Kingan and the Altai, 

 forms a third. These troughs have all been referred to in the preceding pages, 

 but, if I may be permitted to generalize beyond the closer limits of" this paper, I 

 think a much larger one exists in the vast extent of lowlands that stretch unbroken, 

 excepting by the Ural mountains, from the Altai to the Scandinavian peninsula. 



' The eastern edge of the plateau, unlike the southern, is formed by parallel ridges trending 

 between N. E. and N. by E., the valleys between which form succeeding terraces from the plateau 

 to the Sungari river. Prince Krapotkin, who travelled in disguise from the Argun river to Mergen, 

 ascending the Gan river, and descending the Noumin river, gave me the following information : The 

 ascent to the edge of the plateau from the west was hardly perceptible, the descent to the east rapid. 

 In descending he crossed four parallel- ranges trending N. N. B., all of which are traversed by the 

 tributaries of the Sungari. The specimens brought back by Prince Krapotkin, chiefly from the 

 ranges, were mostly granite, porphyries, argillaceous and micaceous schists, and gneiss. Coal is 

 abundant along the eastern slope. 



According to M. Radde the mean height of the Amur between the Kingan mountains and the 

 Bureja mountains, is 800 feet above the sea; between Mochada and the Kur river, from 400 to 500 

 feet. — Radde, in Petermanri's Mittheilungen, 1861, pp. 449 — 45*7. 



MM. Saurin and Murray, of the English Legation in Peking, informed me that in ascending to 

 the plateau from the region west of Jehol, they followed a valley through a mountainous district, and 

 reached the table-land without seeing any signs of an abrupt wall, such as it presents along its 

 southern edge. 



