SECTIONAL TRANSACTIONS.— C. 325 



Prof. Gregory's succession while adding to it in many details. A diagrammatic section 

 across the Arran New Red Sandstone from N.E. to S.W. (fig. 1) shows the dune- 

 bedded, round-grained red Corrie Sandstone (Brodick Freestone of Prof. Gregory) 

 thinning toward the south-west and interdigitating with the Brodick Breccia. Isolated 

 masses of dune-bedded sandstone intercalated within the Brodick Breccia, well seen 

 on the Corriegills shore, are interpreted as fossil dunes. The Brodick Breccia is divided 

 into three horizons which have been found to be remarkably persistent. The 

 constituents of the basal parts of the breccia are mainly vein-quartz, quartzite, and 

 schist of Highland provenance, and fragments of this nature are found, although 

 in smaller amount, throughout the breccia. In the central horizons, however, a great 

 number of basalt pebbles come in, sometimes in such quantity and of such sizes as 

 to suggest the near proximity of the distributing volcanoes, although the sites of these 

 vents have not been discovered. The smaller basalt fragments are often well rounded, 

 and one or two large sub-rounded masses even suggest bombs, but most of the larger 

 pebbles are angular. So far as can be recognised the basalts are similar to those of 

 the Permian vulcanicity of the Ayrshire mainland. Good sections of this horizon 

 are to be found in the Glen Dubh Water, 4 and on the Corriegills shore. Basalt pebbles 

 persist up to the top of the breccia, but here numerous white-weathering agate pebbles 

 appear, and are everywhere characteristic of the upper horizons. 



Following upon the Brodick Breccia, and interdigitating with it to some extent, 

 are thin-bedded red sandstones with some pebble beds. These are well exposed at 

 Lamlash and Machrie. Then comes a thick post of white, yellow, and pink, massive 

 calcareous sandstones, with a carious, yet smooth-surfaced, blocky type of weathering. 

 These are best seen on the southern slope of Glen Dubh, Whiting Bay, and Ballymichael 

 Glen. A few lenticles of conglomerate with well-rounded pebbles occur in it. 



The upper part of the New Red Sandstone includes three distinct series : the Lag 

 a Bheith Marls and Cornstones, well exposed in the headwaters of the Lag a Bheith 

 (the Birch Glen, S.W. of Brodick) ; the Auchenhew Sandstones and Shales, with 

 sharp-angled grains and mica flakes ; and finally another series of marls and cornstones 

 (the Levencorroch Marls and Cornstones). 



The relations of the various horizons are indicated on the diagram, fig. 1. The 

 Corrie Sandstone, Brodick Breccia, and the Lamlash-Machrie Sandstone are believed 

 to be essentially contemporaneous formations. 



Prof. G. B. Barbour. — The Tertiary and Quaternary History of North 

 China. 



An attempt is made to reconstruct the record of events by combining data involving 

 the character of the deposits, inferred climatic conditions, faunal associations, 

 migration of strandline, diastrophic movements, and physiographic stages. 



After the Middle Mesozoic disturbances which finally fixed the major structures 

 of the region, erosion peneplaned the land-surface ; early Tertiary deposits are limited 

 to local warp-basins. At no subsequent time did marine waters much overlap their 

 present confines in North China. 



In late Oligocene and early Miocene times, crustal dislocation and vulcanicity 

 produced an irregular surface upon which erosion again took hold. This T'anghsien 

 stage (Willis) yielded broad open valleys with residual clays and local gravels : the 

 Hipparion (Pontian) fauna and other Pliocene vertebrates point to moderate steppe 

 conditions. 



Towards the close of the Pliocene slight movement led to ponding of rivers in the 

 mountain areas. In the Sangkanho basin, Barbour, Licent, and Teilhard recently 

 found a rich mammal fauna showing affinities with both Pliocene and Pleistocene 

 types. The find is of special interest in view of Zdansky's discovery of two human 

 teeth in Ch'ou-K'ou-Tien cave near Peking associated with vertebrate species, several 

 < if which appear to be identical with Sangkanho types. 



Following on this Sanmen fluvio-lacustrine stage, renewed down-cutting by rivers 

 drained the basins. A closely parallel succession of stages seems to have obtained 

 in Central and South China, though the absence of faunal criteria prevents strict 

 correlation. 



The onset of colder dry conditions of the Malum, stage (Anderson) marked a sharp 



4 J. W. Gregory and G. W. Tyrrell, ' Excursion to Arran.' Prof. Geol. Assoc, 

 xxxv. pt. 4, 1924, p. 414. 



