Continuity mistake: When the Elders are being escorted from the jail to be taken to Laredo, as they walk out it's a dull day and they don't cast any shadows. When the camera angle changes to the other side of the road, the sun is bright and they all have strong shadows.
Other mistake: John Elder whacks Curley (George Kennedy) across the face very hard with an axe handle as Curley was trying to drown the undertaker. Despite this, Curley never shows any mark at all in the subsequent scenes.
Other mistake: Moving them to Laredo early in the morning, except it's noon by the wagon shadows.