418 Reviews — Dr. F. A. Bather — Cystideans from Girvan. 



been recognized as a distinct series. Moreover, a consideration of the 

 distribution of gold-bearing quartz reefs and the mode of occurrence 

 of an important class of auriferous impregnations has led up to what 

 is probably the point of greatest practical importance resulting from 

 the year's work, namely, that the gold deposits of the Territory are 

 closely associated with the last-named series of acid igneous rocks. 



The north-western portion of the Wankie coal-field, including the 

 main basin in which the colliery is situated, has been mapped by 

 Mr. Lightfoot, whose geological work has determined the succession 

 of rocks and the structure of this field. The discovery of fossil plants 

 is interesting, as proving what perhaps was never seriously doubted 

 by geologists, that the Wankie coal-beds belong to the lower part of 

 the Karoo system. The main coal-seam is known to be a very thick 

 one, and the best in the sub-continent for steam-raising purposes. 

 The survey of the district now shows that the basin in which the 

 colliery is situated, although bounded in parts by faults, is simple in 

 structure, and remarkably free from faults and other disturbances. 

 Estimates of the resources of the field made previous to the survey 

 showed a very large reserve. Not only is this now con6rmed, but 

 a large addition may be made with considerable confidence. 

 Mr. Lightfoot points out that probably 600,000,000 tons of coal could 

 be taken out of the district mapped by him. Investigations were 

 made, partly in conjunction with the Chemist to the Agricultural 

 Department, into a number of deposits of limestone and clay, with 

 special reference to their suitability for the manufacture of Portland 

 cement; and a sj-ndicate has proved by trial tests that such a cement, 

 exceeding the requirements of the revised British standard 

 specification in strength, etc., can be made out of materials occurring 

 near Bulawayo, and that a sufficient quantity of them is available. 



Observations on the relation of the soil, or more accurately the 

 subsoil, to the underlying rocks have resulted in the collection of 

 a considerable amount of evidence showing that the soils are largely 

 residual accumulations, and that two of the most important factors in 

 determining their character are (1) the nature of the underlying 

 rocks, and (2) the behaviour of the soil-water. 



I?,E!^v^IE!-V^S. 



I. — Caradocian Ctstidea from Gikvan. By F. A. Bather, M.A., 



D.Sc, F.R.S. Trans. Roy. Soc. Edinburgh, vol. xlix, pt. ii, 



No. 6. 4to ; pp. 359-530, with 6 plates and 80 text-figures. 



Edinburgh: Robert Grant and Son, 107 Princes Street, 1913. 



Price 15«. 6rf. 



(PLATE XIII.) 



IF we examine the various members in almost any grade of the 

 Animal Kingdom we shall meet with some so unlike, superficially, 

 our conception of the type, as to cause us, at first sight, to doubt their 

 right to a place in the phylum to which they have been assigned by 

 the systematist. But a careful study of the larval stages of develop- 

 ment of many such erratic forms has usually led to the recognition of 

 their true position. It is within the memory of the writer that 

 Lepas anatifera was arranged with the Mollusca in the Shell 



