Probably Aragicus Campestris, which is similar to the common store bought mushroom, though it could be Agaricus Augustus (also known as the "Prince"), one of the finest eating of all wild mushrooms. If it is the Prince, the flesh when crushed should have a distinctive almond or marzipan-like odor. We eat these regularly.
WITH THAT BEING SAID, THERE ARE MANY AGARICUS SPECIES WITH SIMILAR APPEARANCE THAT WILL MAKE YOU SICK. UNLESS YOU HAVE A QUALIFIED FUNGOPHILE IDENTIFY THEM IN HAND, YOU SHOULD NOT EAT THEM.
SIMILAR-LOOKING ARAGICUS SPECIES THAT OCCUR LOCALLY AND ARE POISIONOUS, BUT WITH SUBTLE APPEARANCE DIFFERENCES (INCUDING LACK OF ALMOND ODOR, OR PRESENCE OF A FOUL ODOR OR STAINING OF THE FLESH WHEN BRUISED), INCLUDE Agaricus placomyces, Agaricus praeclaresquamosus, Agaricus xanthodermus, and several others. The results of eating a poisonous variety of Aragicus include sweating, flushing and severe stomach cramps.
From the photo they appear to be Aragicus Campestris but the warnings should be taken seriously. A friend regularly ate Aragicus Campestris which grew in his lawn in Seattle. He was visiting his brother in Kansas and saw the same mushroom growing on the lawn there. They both tried one small bite. 24 hours later they were discharged from the emergency room, still not feeling well, after having their stomachs pumped. Eating wild mushrooms is one of the delights of the northwest where we have so many varieties but you do have to know what you are doing. The same is true if you harvest your own clams, mussels, and oysters. The wrong place or time and you can get very sick and even die eating them. Eating chinook belly strips or Puget Sound blackmouth regularly probably have more long term health risks than most wild foods.
I just finished three days of razor clam and chantrelle meals, If I could have left Seattle before noon Friday I might have been able to stop at the Hump for salmon too. We can't complain, what we got in our 10 hour round trip was better than anything we could buy at the store. I like to know where, what I eat comes from, it is what you don't know that gets you.