90 
E. DE C. Clajrke, C. Teichert and J. R. H. McWhae. 
spots up to 15 iiiin. in diameter and irrefjularly scattered reddish-brown 
spots. ^Microscopic examination and heavy mineral determinations showed 
that it is largely composed of extremely tine particles of clay minerals 
Avith a. smaller amount of fine-grained, angular quartz, iron ores, and 
liypersthene; the hypersthene was no doubt derived from the adjoining 
norite dyke Avhich was mentioned in the introduction. The Avhite shale 
is exceedingly iine-grained, Avhite, and slightly friable and contains a 
minute amount of very fine-grained quartz, iron ores, and hypersthene. 
Sponge spicules occur in both rocks but are not uiimeroiis. 
2. The tmfossiJifcrous dolom.ite (Campbell, lOOG, p. 21) is a hard, 
Avhite, tine-grained rock. Staining tests (Kodgers, 1040) show that it is 
an almost mono-minoralie dolomite containing occasional fragments of 
quartz up to one mm. in diameter and still rarer rounded bodies of 
ferruginous material up to three mm. in diameter Avhich may be concre- 
tions but are more ]u'obably pebbles. Neither fossils nor any sign of 
bedding can be seen in this rock Avhich is included in the Tertiary sci'ies 
because it overlies the Pre-Cambrian rocks and occurs near strata knoAvn 
from their fossils to be Tertiary in age. 
3. There, are seAvral varieties of fossiliferous Iimesto?ic. Some are 
unaltered, others have been changed diagenetically to siliceous or to dolo- 
mitic rocks. They vary in character even in one outcroi"), and Avill 
therefore ho discussed in the next section. 
IV. DESCRIPTION OF OUTCROPS. 
1. CAMPBELE’S •‘OPALIZKD SEA BEACH.” 
A very gently undulating area of about 100 acres covered with 
unfossilifcrous dolomite (Campbell, lOOO, fig. 11) occurs near the Norse- 
man end of the causeway over Lake CoAvan, about three-and-a-half miles 
north of Norseman on the south side of the great norite dyke. At the 
eastern end of this occurrence there are two small fossiliferous outcrops, 
about 40 yards apart Avhich underlie the unfossilifcrous dolomite. About 
100 yards fartlier east is a knoll oA’er Avhicli are scattered many fragments 
of chrysoprase. The fossiliforous rocks are opalized and it is difficult 
to determine their original characteristics, Init there appear to have been 
three types; — 
(a) Fine laminated sandstone. 
(h) Very fiiu'-gi-ained mudstone Avith conchoidal fracture and few 
fossils. 
(c) Sandy limestone with ojialized fossils and rounded to angular 
sand grains. 
The sandy limestone is more fossiliferous than the other tAvo, but the 
fossils are A'ery much altered diagenetically and good specimens arc hard to 
obtain. 
iMiss Irene Crespin (see Appendix) has determined the folloAving 
P>i'yozoa from this locality : — 3£acropora chirl-ei (T. Woods), Amphihlestruin 
sp., Hitfrlisina r/emimta (Waters), Cellepora fossa (Ilaswell), Adeonellopsis 
elavata (StoL), lietepom aeiculifera iMcG., Crisia acropora Busk. 
Rome years ago Chapman and Crespin (1934, p. 12G) gave a list of 
fossils, other than Bryozoa and sponges, from “Norseman”. Since no other 
