[Cob] Puget Sound Soil

[Dan Burbank]

Hi all. Again, yet another newbee here. I am north of Seattle about 20  
miles in Lynnwood. Has anyone in the north central Sound done any cob  
work? I am looking at soil on my property and finding that it is  
glacial till. It appears that it is mostly sand and rubble with little  
(if any) clay. Though I continue to dig hole and shake jars.  I know  
of clay yards by Issaquah but I would like to not have to travel so  
far for clay. Anyone with familiarity of this geography?

I appreciate any help or suggestions. I want to build a Solar Passive  
Greenhouse in year or 2 and have plenty of time to research. Just  
looking for a little feed back on this type of soil, if you have any.

Dan Burbank