Erupting Slate

I had to turn around and go back to look at this... This is is a face of a sheer slate wall. Hundreds of millions of years ago, this part of the Rockies was all a flat, horizontal ocean floor. When Rockies were undergoing the process of being built up this seabed broke up and became tilted & twisted and whatnot in various ways... This particular part of the ocean floor had been tilted up to about 75-80 degrees. It is nearly vertical. What caught my eye is that there are sections of this wall made of of strata that are practically perpendicular to the rest of the wall... How did this happen?

Canada
Geology
Rockies
Slate
Strata
Puzzle