What you see is the original structure of the Farmington LDS Rock Chapel. As far as I know, the building has had at least two major renovations. When my family moved to town, the building was shaped like a cross (when looking directly overhead). The memorial chapel--the one with the mural--went west, classes and the kitchen went east and the gym/stage went south. The latest addition expanded the north end and added another chapel, this one with padded seats (oh, thank you tithing payers...). And with the addition, the building still looks like a cross from above.
I absolutely love this building. The solid rock walls of the memorial chapel are at least 3 feet thick and will probably crumble in the event of a semi-strong earthquake. It's cold in the winter and warm in the summer, but it's a wonderful church. It's a place where the children's program, called Primary, was organized more than 125 years ago. It's a place where the community watched movies through small windows above the gym, the same windows we as children stuck our heads through and wondered why in the world those little windows of different shapes and elevations were there to begin with.
This is the building where my wife and I had our wedding luncheon, where children were blessed and ordained and where funerals were held for both my father and my mother. I understand the church will close the building for several years to make it earthquake-proof and I hope that's true. It's a special place.