Tertiary Deposits Near Norseman, Western Australia. 
93 
±he higher ground so that their eonlaet with the sediments can he mapped, 
\vdier(?as the northern boundary is obscured by alluvium. 
The dumi-s along the deep lead contain spongolite, siliceous oolite, and 
an oolitic carbonate rock. The oolitic rocks are not found at the surface, 
and, all the shafts being inaccessible, it can only be assumed that they occur 
somewhere in the Tertiary series. 
About 200 yards north of the last s])ongolite outcrop is an exposure 
of dolomite north-west of which there are six or seven others all mapped by 
Campbell (Campbell ItlOO, fig. 3). They are all unfossiliferous. The 
relation of the spongolite to the dolomite has not been seen hut the base of 
the sxrongolite is about level with the top of the dolomite. 
The only palaeontological work on the spongolites was done by llinde 
(191(1). He cojisidered that the spicules wer(‘ idenlicai with or closely 
similar to, those of the following forms previously described: — Monaxonid. 
Latruncidia ; Desmucidon {llormteodictt/a) (jrandis LJidley and Dendy; 
Petrosia varddiUiH Kidley; II(dichondria infreqnens Carter; Sirongylophora 
dtwissitna Dendy ; Forcepia crossanchorata C'arter ; T ethga Lam., Myxdla 
hastata Kidley and Dendy. 
Tetrnctinellid. Stelhdta reticnhda Carter ; ErgJus Gray ; Craniella 
Schmidt; Cgdoninm. muUeri Fleming; (podia zetlandica Johnston. 
Lithistid. Ragadinia Zittel ; three species of Disoodermia Boeage ; 
CoraUistes Schmidt; TheoneUa sivinlioei Gray; Vetidina Schmidt; Dactglo- 
cidgcitfs Carter. / 
Ilexactinellid. Rosstdla aidarctica Carter. 
3. PENINSULA. 
The shore of the Peninsula is broken into small bays, islands, sandspits, 
and promontories (Plate II). Outcroi)S which we call A, B, and C, of 
horizontal or very nearly horizontal fossiliferous limestone occur in three 
of the bays, the shores of which are generally steej^ banks, in i)laces under- 
cut, two to 15 feet high, formed by various agents of arid erosion and by 
very occasional coirasion by the lake water. In some of the bays there is 
a ‘daterite^' layer two to three feet above the bed of the lake but well below 
the present soil surface. 
Locality A is the west bank of the most southern of the bays. The out- 
crop at locality B in the third bay north of this extends across the floor of 
the lake to the north side where it disappears under a sand ridge lOO yards 
wide, on the otht*r side of which, in the next bay, is locality C a limestone 
bank 12 feet high and 130 yards long. 
Thin sections show that the Tertiary rocks at the Peninsula ure com- 
posed of fiiio-gi’ained matrix of dolomite unci ferruginous material in which 
there is a varying percentage of comy)lete or fragmentai-y fossils with 
angular, medium-grained fjuariz [tarlicles and more rounded ferruginous 
fragments and concretions, up to two mm. in diameter. Staining (Rodgers, 
1940) shows that calcile occurs only in some of the casts, re])lacing the 
original shelly matter, but in most instances the replacing material is 
dolomitic, and, in some places it is secondary ferruginous matter. 
