shield vs cavalry

I dropped my blasting rod to grip my staff in both hand, and extend it before me. The moment I did, Sidhe riders began making swift warding gestures, accompanied by staccato bursts of magical pressure, separate protective charms rising up before each of them to block whatever magic I was about to throw.
The horses, however, didn't do any such thing.
I raised a shield, but not in a wall in front of me. Such a warding would have brought the faerie nobles into contact with it, and no one wizard could hold a spell against the wills of a score of faerie lords. I brought up a shield only a couple of feet high, and stretched it in a ribbon across the ground at the feet of Slate's mount.
The Winter Knight's steed, a giant grey-green beast, never knew what hit it. The low wall I'd called up clipped it at the knees, and it came crashing down to the misty earth with a scream, dragging Slate down with it. Talos, on Slate's right, could not react in time to stop his mount or to avoid the wall, but he threw himself clear as his horse went down, dropped into a roll as nimble and precise as any martial arts movie aficionado could desire, and came up on his feet. He spun, a dance-like step somehow in time with the vast song of the battlefield, and his sword came whipping at my head.


Summer Knight Chapter 32, Page 354-355