These images were all from a small area of the track. Could they be different lifecycle stages of a slime mould? The white clusters shown in the last photo are quite common on soil in the area, but I haven't noticed the other 'stages' before.
This appears to be fungal rather than myxo. The white ones in image 5 may be Chromelosporium/Ostracoderma sp. while there is a slight possibility that image 4 may be a plasmodium its difficult to be certain without more detail. You appear to have captured 2 different species in these images. Any chance you can re visit the area and observe any further changes? This is an interesting sighting Cath many thanks.
Teresa, I didn't manage to get back to this site, but sighting 4593149, which has much better pictures, seems to show similar forms that are closely associated.