140 



KHomefres. tne Avon embayment of the Windsor series 

 (Mississippian — Lower Carboniferous) , This 

 embayment extends up the basin of Avon river 

 in a southwesterly direction into the Southern 

 upland for a distance of about 5 miles (8 km.). 

 Along the southern border the rocks underlying 

 the Southern upland are largely granite and 

 the rise to the upland is abrupt, but on the 

 west the area of the Windsor series is limited 

 by the Horton formation, which forms a belt 

 of foothills of variable width, between the 

 Windsor lowlands and a spur of the Southern 

 upland. 



The Windsor rocks are exposed in broken 

 sections on the Avon river above and below 

 the railway bridge. 

 5 m. Mount Denson Station — Alt. 40 ft. 



8 km. (12-2 m.). Less than | mile (o-8 km.) north 

 of Mount Denson station the railway approaches 

 close to the shore and from here an outcrop 

 of Windsor anhydrite may be seen at a low 

 point known as Aberdeen beach. This rock 

 is very different from the gypsum at Windsor, 

 as it is massive, evenly bedded, less disturbed, 

 and of a snowy-white colour. It lies in a low 

 syncline succeeded to the south by a flat 

 anticline. 



The margin of the narrow Windsor embay- 

 ment is crossed at this point, and the railway 

 from here onwards, passes over a northeasterly 

 trending area of Horton rocks which extend 

 out from a spur of the Southern upland. To 

 avoid the hills farther west, the railway clings 

 closely to the shore. It is this projection or 

 spur of the Horton strata that is cut trans- 

 versely by the Avon river, thus exposing the 

 Horton section. 



11 -9 m. Avonport Station — Alt. 57 ft. (17-3 m.). 



19- 1 km. Avonport is within 1 mile (i-6 km.) of the 

 northern termination of the Horton spur or 

 where the Horton rocks sink beneath the 

 Triassic lowland of Cornwallis valley. A short 

 distance east of the railway station the exposures 

 of the Horton series commence on the banks 

 of the mouth of Avon river. 



