In this post, I'll talk about what Ernst Nicholson says on page 173 about Erhard Blum's views regarding KD, a Deuteronomist in the early post-exilic period. Remember that Blum's argument is that the Deuteronomist added a redactional layer to stories in the Pentateuch, and a priest (KP) later added another layer.
On what does Blum base his identification of a KD layer in the Pentateuch? Essentially, he notices similarities between parts of the Tetrateuch and Deuteronomy or the Deuteronomistic History. For example, in Exodus 14:13, 31 and I Samuel 12:16-18 (from the Deuteronomist), there are parallels: people believe in a man of God after seeing a wonder from the LORD. But Nicholson contends that similarity with the Deuteronomist does not make a work Deuteronomistic, for a non-Deuteronomistic work can imitate Deuteronomistic language.
Blum maintains that KD has a significant hand in the Sinai pericope and the seventy elders stories. For Blum, KD begins with Genesis 12:1-3 and ends with Israel's dwelling in the wilderness. Regarding the primeval tradition (Genesis 1-11), Blum attributes that to the priest, who "utilized some older written tradition."
UPDATE: I've learned that Blum actually distinguishes KD from the Deuteronomist, for he believes that KD was later---an heir to the tradition of the Deuteronomistic School.