E. 8. Simpson — Laterite in Western Australia. 399 



juices exuded by the worm, in this ease black. Underneath this, about the 

 centre, are indications of the polygonal areas found anteriorly in Arenicola. 

 A few papillae are present here. Otherwise this specimen is very similar in 

 surface characters to the type, specimen A. 



Apxxndages. There are very few indications of appendages in this specimen, 

 and they are similar in character to those in specimen A, but are only distinct 

 on one side, the left, where they are distant. They are notopodial setae without 

 a doubt, but though only seen on one side there is no trace of neuropodial 

 crotchets as in specimen A, and they may both therefore be regarded as viewed 

 from the dorsal aspect. 



Arcbaeenicola, not. gen. ' 

 An annulated Polychaete, with an impression of the cuticle bearing 

 annuli of two sizes, possibly forming segments. The cuticular 

 surface is covered in the type by epidermal papillae, in the co-type 

 by polygonal areas between the somites. The appendages are paired, 

 on alternate annuli, consisting of capillary notopodial setae. The 

 head bears no appendages, but indications of a frilled prostomium. 

 The impression is surrounded by a zone caused by exudations of the 

 juices, as in the present-day Arenicola. 



Archarexicola rhjetioa^ sp. NOV. (eENorrpE). 



Characters of the genus, based on specimen A (type) and specimen 

 B (co-type). 



Specimen A (PI. XXI, Fig. 1). Horizon: Lower Rhaetic — Black 

 Shales. Locality : Glen Parva, Leicestershire. 



Specimen B {^\.~SLSA^ Eig. 2). Horizon: Lower Ehoetic — Black 

 Shales. Locality : ? Spinney Hills, Leicestershire. 



Both specimens are deposited in the palaeontological collections of 

 Leicester Museum, where they form the third type species of local 

 origin. 



I am greatly indebted to the discoverer of the type, Mr. A. J. S. 

 Cannon, for the opportunity of seeing this and other B-hsetic fossils 

 of interest, and for much help in other ways. I have to thank 

 Miss G. M. Woodward also for the care which she has taken in 

 preparing the plate. 



EXPLANATION OP PLATE XXI. 

 Fig. 1. Archarenicola rhcetica, sp. nov. Specimen A. Lower Ehastic : Glen 

 Parva. Nat. size. 

 ,, 2. Archarenicola rhcetica,, sp. nov. Specimen B. Lower Khsetic : 



? Spinney Hill, Leicestershire. Nat. size. 

 ,, 3, 4. Burrows of Ar char enicolct rhcetica, in Black Shale, Glen Parva. 

 Nat. size. 



IIL KOTES ON LaTEKITE IN WESTERN AuSTEALlA. 



By Edward S. Simpson, B.E., F.C.S., Geological Survey of Western 



Australia. 

 (Communicated by permission of the Government Geologist of Western 



Australia.) 



rpHE following notes on the laterites of Western Australia are the 

 JL outcome of a careful study of the series of articles contributed 

 to the Geological Magazine during the latter part of 1911 by Dr. L. 

 Leigh Permor, entitled "What is Laterite?" These deal with the 



