Which one of the following constructions is correct?
1-he found {a slope of grass} {and a little heather running up before him to some trees}.
2-he found {a slope of grass and a little heather running up before him to some trees}.
when he went through the gate he found a slope of grass and a little heather running up before him to some trees.
There is a slope. There is grass and heather growing on it, mixed together. It’s mostly grass with only a small amount of heather. Up the slope are some trees.
Side note: both grass and heather are treated like non-countable nouns even though they consist of individual plants that can be counted.
Thank you. That was really helpful. 
He found a slope (of grass and a little heather running up before him) to some trees.