I suppose I'm rambling. Suffice to say I don't know yet why it was called the "marsh of reeds": Cladking

Long ago, tall slender hollow reeds grew on the banks of the Jordan and the Nile river. The word for 'reed' in the Hebrew, Arabic and Egyptian languages was 'kaneh'. Latin - 'canna'. The word passes over into Greek and Latin, and into the languages of western Europe. A rather remarkable word family grew from the root word 'canna'. Some are easy to trace back - sugar 'cane', walking 'cane' and even a 'cannon', are all clearly related to the reed in shape. With just a little imagination, the word 'canal' and 'channel' can also be associated with a pipe or grove.

It is probably more difficult to see how the word 'cannon', as in 'law', derives from the root word meaning 'reed'. Since reeds were long and straight, they were often used as measuring rods. From this concept, 'reed' came to mean a 'standard' and ultimately an 'authoritative standard'. With the Field of Reeds representing the Great island of Osiris, the red crown and throne are perfect symbols of law and governance, a governance that is predicted for Osiris to include the entire world.

The word 'marsh' is also interesting when we study it's root origin, which can be found in the fourteenth century Anglo-Saxon. The word 'marsh' has it's root word in merus/mere:

1. Pure and unmixed as wine; a people or a language.

2. Fully; as much as; what is specified; completely fulfilled; developed or absolute.

It is interesting then when we apply these root definitions to the two words of 'marsh' and 'reeds':

Marsh of Reeds - pure or fulfilled laws

Marsh of Offerings - pure or fulfilled offerings

Field of Reeds - field of laws

The Utterance below has been included here to show this marsh/purity connection:

Utterance 304:

'Greetings to thee, O daughter of Anubis, who is at the windows, of heaven, thou friend of Thoth, who is at the double rail (end) of the ladder. Open the way for N., that N. may pass. Greetings to thee, O ostrich, who is on the shore of the Winding Watercourse. Open the way for N., that N. may pass. Greetings to thee, O ox of Ra, with four horns, thy horn in the West, thy horn in the East, thy horn in the South, thy horn in the North. Incline thy western horn for N., that N. may pass. Art thou a pure westerner? I come from the falcon city. Greetings to thee, O Marsh of my Offerings; greetings to the honourable ones who are in thee. N. will honour those who are there. Comfortable are the pure who are in me.'

The inclusion of Utterance 304, is to show that the term marsh denotes pure or purity. Clues are given throughout the Utterance to this.