During the Cambrian period, the Malvern Hills were located on the south-eastern margin of the Iapetus ocean (Figure Four). A global rise in temperatures resulted in the melting of an ice sheet located within the southern hemisphere. This resulted in a major rise in sea level (marine transgression) which flooded the Precambrian land mass depositing a series of sedimentary rocks. The oldest Cambrian rocks in the area are represented by a conglomerate referred to as the Malvern Quartzite. The Malvern Quartzite contains fragments of material derived from the Malverns Complex and the Warren House Formation. These conglomerates are normally associated with sea level rises and renewed deposition after a lengthy period of uplift and erosion. Sea levels gradually rose depositing the Hollybush Sandstone. This sandstone is rich in the mineral glauconite indicating that it was deposited in shallow seas with a water temperature of between 10 Degrees and 15 Degrees Centigrade. Towards the end of the upper Cambrian sea levels rose again, resulting in the widespread deposition of the Whiteleaved Oak Shales.
There are only a few exposures of Cambrian rocks in the Malvern area as they have largely been removed by a combination of erosion and tectonic activity operating during the Ordovician Period. Most of the Cambrian rocks are located at the southern end of the hills, running west of Midsummer Hill (SO759375) to Chase End Hill (SO761355) forming an area of low relief.