Mushroom ID

Imagine our surprise when we came upon these mushrooms near our irrigation ditch. (Sorry about the picture quality, but it was near dusk.) I thought mushrooms made their presence known after a rain, or in moist areas. This spot is anything but moist. True the acequia is nearby, but I can't imagine there is any moisture in this spot, especially because we haven't had a drop of rain in eons.

The tallest stands at about 12 inches and there was another beginning to emerge to the right of these. Note the spores at the bottom of the picture. Other than their height, the other thing that was astounding was that the grey/white caps actually come off!

This photo does not do this 'shroom justice. The red rust color of the cap was brilliant. This pic taken with the flash gives you a better idea.

I tried to id them last night, but to no avail. If anyone has any insight, please leave a comment.