Calculating descriptive stats from many maps

Hi

I have 25000 maps, generated by simulation predictions, covering the
same area, and would like to calculate some descriptive stats, like
mean, standard deviation, median, quartiles of all cells, to create a
"variability map".

Is there an easy way of doing this in R?

Thanks,

Rainer

Rainer M. Krug, PhD (Conservation Ecology, SUN), MSc (Conservation
Biology, UCT), Dipl. Phys. (Germany)

Centre of Excellence for Invasion Biology
Faculty of Science
Natural Sciences Building
Private Bag X1
University of Stellenbosch
Matieland 7602
South Africa