Thanotopsis

This poem is talking about death. They want you to just except death and not worry about it, and he paints a picture of it being dark but then melds it into concepts of them earth. When you die your body will be burried in the ground and you shall return to the earth, joining all the others that have died before you and becoming a brother of all elements such as rocks or clods. You will also eventually be joined by more and so you should never feel alone in the sence of death and should rather die peacefully as if going "down to pleasant dreams."