82 E, 0. Teale: 



in<i- Upper Ordovician rocks are found as a very thin belt on the- 

 north side of the Serpentine, and repeated just to the south of the 

 limestone. All the strata are highly inclined, being almost vei'ti- 

 cal, but an overthrust from the north, or north-east, causing a 

 fault in the vicinity of the Ordovician contact, has placed the lime- 

 stone locally above the graptolite slate, as sliown in the sketch 

 section. No. 3. This movement is probably to be correlated with 

 the general overthrust of post-Silurian date, affecting a consider- 

 able part of the Dolodrook area, for a fine example of overfolding 

 of the Silurian rock is shown in thie Dolodrook, about one mile and. 

 a quarter in a straight line below Thiele's Creek junction 

 (Photo. 2). 



The Silurian sandstones and shales outcrop at each end of the 

 section forming the next enveloping zone of the complex inlier. 

 The general ge-anticlinal structure is therefore complete along this, 

 line. 



The Dolodrool- Limestones. — These form one of the most impor- 

 tant series, for they have provided the definite palaeontological 

 evidence without which it would have been impossible to discover 

 the complete key to the structure of this region. 



Previous to resuming the field work in this region, the fossils, 

 chiefly trilobites which Mr. Chapman had definitely concluded to be 

 Cambrian, came from the limestone outcrop No. 1, at the north- 

 west end of the belt. 



The first fossil obtained in the district from the limestone, origin- 

 ally regarded by Mr. Chapman as Silurian, came' from Roan Horse 

 Gully outcrop, about three and a-half miles to the south-east, but 

 no trilobites had yet Ixien found in this occurrence. The recent 

 field work, however, has been successful in discovering similar trilo- 

 bites in four separate outcrops, including i{\Q Roan Horse Gully 

 limestone, and the mapping generally shows clearly that all the 

 limestone outcrops, of which there are nine, belong to the same 

 series. The additional fossils obtained, Mr. Chapman states, give 

 further convincing evidence of the Cambrian age, and his supple- 

 mentary palaeontological description will be given later. 



Upper Camhrian Fossils. — The following are the fossils described 

 by Mr. Chapman (15) from the Dolodrook : — 

 Plantae — 



Class, Algae. Girvanella Sp. 

 Animalia — ' 



Class Crinoidea 



Crinoid stems, joints and ossicles. 



