In those days.. - 8:1

In those days, NIV- during those days, Z & G- at that time... they go on to say, 'but here serving to link two paragraphs and not meant as a chronological note'. How do they know that? It reads as though it is a rough chronological marker. Just reading France and he seems to take a more straightforward reading- and thinks it probable the feeding took place in the Decapolis region, where Jesus is at the end of the last pericope.
It certainly fits. A crowd gathered fairly quickly after he arrived. He healed a man who spoke with difficulty and was almost deaf (an interesting point that Mark describes him like this, and the crowd describe it as 'he even makes the deaf hear and the mute speak- perhaps another pointer to Mark's concern for truth), and those he commands not to tell about this ignore him and kept talking about it.
It would be natural for a large crowd to gather under these circumstances, at about this time. And if this is the case, as France points out, we have a major miracle being performed in a non Jewish area.