We got 'em headed this way--" Bill's voice: "-- and I seen him hittin' for the line and headed him off--" More mumbling.
Mary V's voice: "I can't see why he doesn't hurry! Why, for gracious sake, must a person lie forever out in the sun when he's all smashed--" Bland's voice: "-- not as much as yuh might think, in all this brush.
I ain't gone over it yet--" (mumble) "-- short circuit--" (mumble, buzz-buzz) "went past me so close I could feel the wind--" (mumble) "-- I dunno.

I've seen 'em hurt worse and get over it, and I've seen 'em die when you'd think--" After that it was all mumble and buzz, and then more stars, and blackness and silence.
Piecing together the fragments, as Johnny could not do, here is the interpretation.
The three riders whom Johnny had seen as the plane was dipping to its final fall were Mary V, Tomaso, and Tomaso's brother.

Mary V had gone off to ride the country which Tex had said was too difficult for her--"and it was _not_ too difficult for a person who had any brains or any gumption and who did not lose all the sense a person had," etc.

She had gone some distance toward the southeast boundary, and Jake was behaving like a perfect dear.

She had seen a few horses, and they had all run every which way when they got sight of her, so she was keeping right along and planning to just gently urge them toward Sinkhole as she came back.
Well, and on the way back she had seen the young Mexican riding along, and he had looked perfectly harmless and innocent, and he had a rag tied around his head besides, and kept putting his hand up, and wabbling in the saddle exactly as though he was just about ready to fall off his horse.