234 JRevieics — Geology of Western Australian Gohlfields. 



One of the fossils, a Goniatite of the genus Gastrioceras, is of 

 special interest, being of an unusual size. The following are the 

 species identified : Foraminifera — Nuhecularia Stephensi, Howchin. 

 Actinozoa — Pleurophyllum Ausfrale, Hinde. Polyzoa — Fenestella 

 fossula, Lonsdale. Brachiopoda — Bielasma sp., Semmida suhtilita, 

 Hall (?), Spirifcra sp., Reticidaria lineata, Martin, Prodtictus semi- 

 reticulatus, Martin, P. tenuistriatus, var. Foordi, Eth. fil., P. undatus, 

 Defrance, P. subquodratiis, Morris (?), Chonctes Pratti, Davidson. 

 Pelecypoda — Aviculopeden Sprenti, Johnston, Avicidopecten sp.. 

 Conocardium sp., Sttdchburia sp. Gasteropoda — Bellerophon costatus^ 

 J. de C. Sowerby, var. Cephalopoda — Gastrioceras JacJcsoni, sp. nov. 

 In the fifth and last paper Mr. W. Howchin describes a small 

 collection of Foraminifera from a calcareous marlstone at Gingin, which 

 are regarded by Mr. R. Etheridge as probably of Upper Tertiary age, 

 though the evidence is insufficient to establish the exact horizon. 



A. H. F. 



VII. — Geological Survey, AVestekn Australia. Bulletin I^o. 28 : 

 The Geology and Mineral Resources of Lawlers, Sir Samuel, 

 AND Darlot (East Murchison Goldfield), Mount Ida (I^orth 

 Coolgardie Goldfikld), and a Portion of the Mount Margaret 

 Goldfield. By Chas. G. Gibson, Assistant Geologist. 8vo ; 

 pp. 73, with 3 maps and 5 mining plans. Perth, W.A. 



IN this report some of the most important of the raining centres 

 of the State are dealt with. The area surveyed is described 

 in the title above. As stated in previous reports, the rocks of the 

 district consist of a complex of crystalline rocks, the age of which, as 

 far as the evidence indicates, is Pre-Cambrian or Archfean. There 

 is an acidic and a basic series, that is, there are ' granites ' and 

 ' greenstones,' the granites occupying the larger area, but not being 

 the oldest rocks, as thej^ are often intrusive in the greenstones. Both 

 are traversed by numerous granitic and felspathic dykes, as well 

 as by dolerite dykes traversing the granite of the Lawlers district. 

 Quartz veins occur, apparently of later origin than the granite, 

 generally at the junction of the latter with the basic rocks, indicating 

 a possible genetic connection between the granite and some of the 

 quartz veins. 



Mr. Maitland, in his prefatory note, lays stress upon the fact that 

 the quartz reefs are of later date than the granite intrusion, because 

 this indicates that the reefs are not likely to be cut off, which might 

 have happened had their formation preceded the intrusion. The 

 question has obviously an important bearing upon the results of gold- 

 mining in the area under review. 



Tlie report is well illustrated with photographic reproductions 

 showing the physical features of the country, and with maps, plans, 

 and sections of the mines in operation. 



A. H. F. 



