Do you have any images or remember what the stem (stipe) of this fungus was like? I've identified it to a gilled fungus, Agaric, however there is not enough detail to take it further, sorry. It looks like the caps were a grey-brown colour that has been largely washed off by rain. The trees they are under maybe suggests they might be one of the Amanita species. These have white gills and usually a ring (annulus) on the stipe and/or a bulbous base or a cup (volva) like structure at the base of the stipe. This may be underground. If you have the opportunity to see these again if you could have a look for these features it would help greatly in the identification.