Ararat Marine Siltstone Land Unit

The dominant landform of this land unit is dissected undulating rises, although there are also some rolling low hills and some undulating plains that are mainly the footslopes of the rises. The major soils found on the gentler footslopes of the undulating rises and plains tend to be reddish, strongly structured and well drained (Chromosols) although soils with a strongly acidic subsoil (Kurosols) can also occur. There is evidence of a bleached horizon, indicative of impeded drainage, in some of the soils, mainly on the lower slopes and drainage depressions where there is more water accumulation. Both the topsoil and subsoils tend to be acidic, sometimes strongly so. The soils on the dissected rolling low hills are generally shallow, although they can be quite strongly structured. They are commonly Sodic Red Chromosols. Cleaved sedimentary rock outcrop is common on this land unit, especially on the exposed westerly aspects. Gully erosion on the plains below these hills and on the drainage depression is quite severe.


Plates 6, 7 & 8 Dissected colluvial Ordovician sediments near Mt Challicum facing southwest
with prominent gully and tunnel erosion.