516 Notices of Memoirs — Br. F. Oswald — 



independently of other masses of this lateritic rock. On account of the limited 

 extent of each of these masses of rock, their different elevation, their want of 

 horizontal bases, and the numerous cases in which the rock contains residual 

 angular fragments of other rocks, most geologists would probably prefer to 

 consider these occurrences as distinct from the masses of typical laterite 

 occurring in horizontal sheets, often of considerable extension, and free from 

 included fragments of rock different in character from the laterite. For this 

 reason I propose to refer to these occurrences under the name of lateritoid to 

 indicate their similarity to laterite. It is to be noted that, were they to be 

 designated 'laterite', they would by their position come into the high-level 

 laterite division. From what I have written above it is evident that my view of 

 the origin of these masses of lateritoid and their included manganese-ores is 

 practically identical with Maclaren's theory of the origin of laterite in general. 

 He bases his theory particularly on the occurrence at Talevadi in Belgaum. 

 I have visited this occurrence myself, and although the sections were no longer 

 so good as when Maclaren went, yet I saw sufficient to make me agree with his 

 description of the occurrence. Although the occurrence was in an area where 

 the laterite seemed to occur as a large spread, yet I could not see any difference 

 between the mode of occurrence of the manganese-ores here and those in the 

 lateritoid deposits. From this it will be seen that the Talevadi occurrence 

 may be regarded as a connecting link between the lateritoid caps containing 

 manganese-ores and the large spreads of high-level laterite usually free from 

 manganese-ore. I think, however, it is more closely related to the lateritoid 

 occurrences than to the large spreads of high-level laterite in which bauxite is 

 so often found." 



(To be concluded in the next Number.) 



NOTICES OIF DVCEDVCOIE.S. 



I. — Jurassic in the Western Caucasus. 

 [Translated from the Eussian by Felix Oswald, D.Sc, B.A., F.G.S.] 



ALTHOUGH Jurassic strata reach a very extensive development in 

 Daghestan and in the Central Caucasus, it is only within recent 

 years that Russian geologists (N. I. Yorobiev in 1906, 1. P. Tolmachev 

 and M. Volosatov in 1907) have definitely proved the existence of 

 Middle Jurassic beds in the western part of the Caucasus, viz. in the 

 valley of the Little Laba, in the Psebai district (Maikop division of 

 the Kuban province), where they overlie the Triassic strata described 

 in the Geological Magazine, Dec. V, Vol. VI, No. 538, pp. 171-3, 

 April, 1909. The fossils (now in the Peter the Great Museum at 

 St. Petersburg) have been determined by B. Rebinder in a paper 

 written in Pussian (" Trav. Mus. geol. Pierre le Grand, St. Petersb.," 

 ii, pp. 53-60, 1908), which I have translated and briefly summarized 

 in the following abstract. 



The Jurassic of the Little Laba valley extends for 3 miles below 

 Psebai, forming the line of the Gernegem Heights, which are traversed 

 and partly dissected by the Little Laba and its small tributaries. 

 The valleys of these tributary streams are named in successive order 

 from north to south : Lazaret, Marin, Sushkov, Vorov or Pazboinich, 

 and Solen. The general slope of the country roughly coincides with 

 the north-east dip of the Jurassic strata, and hence the limestones rise 

 to increasingly greater heights when traced southwards towards Psebai, 

 so that in the southernmost of the tributary valleys, viz. Lazaret, 

 the underlying series of shales with sphserosiderite nodules is 

 exposed beneath the limestones, which form craggy heights, liable to 



