As the Nephites carried with them the brass plates of Laban, so the Jaredites carried an ancient record, but Moroni’s abridgment does not tell us much about this record. We know that it must have contained the story of Creation, the Garden, and the Fall (Ether 1:3-4). Apparently, it also contained an account of secret plans and combinations. Likely, this record was a lot more extensive than the few chapters we have in Genesis. It probably included a more comprehensive account of the story of Cain as it appears in Moses 2:25-32:
’(the word of the Lord to Cain) And it shall be said in time to come—That these abominations were had from Cain; for he rejected the greater counsel which was had from God; and this is a cursing which I will put upon thee, except thou repent.
And Cain was wroth, and listened not any more to the voice of the Lord…
And Satan said unto Cain: Swear unto me by thy throat, and if thou tell it thou shalt die; and swear thy brethren by their heads, and by the living God, that they tell it not; for if they tell it, they shall surely die; and this that thy father may not know it; and this day I will deliver thy brother Abel into thine hands.
And Satan sware unto Cain that he would do according to his commands. And all these things were done in secret.
And Cain said: Truly I am Mahan, the master of this great secret, that I may murder and get gain. Wherefore Cain was called Master Mahan, and he gloried in his wickedness.
And Cain went into the field, and Cain talked with Abel, his brother. And it came to pass that while they were in the field, Cain rose up against Abel, his brother, and slew him.
Here is a record of how the secret combinations, certified by an oath, were established on the earth. But it does not explain how these were used to obtain kingdoms and great glory as the daughter of Jared suggests. Obviously, their record was a lot more comprehensive than what we have today.
“Did they come upon this great western hemisphere without a knowledge of God? No. Without any written record? No….the Jaredites did not come here without a record of the things from the days of Adam, down; they had it with them. They kept it with them, and multiplied copies in the midst of their nation.” (Journal of Discourses, 16:52)