Elmer:Is this a Conocybe
Found on Sauvie Island
Growing in Grass
Gills are free and serated
spore print in brown - maybe rusty brown
Stem breaks like chalk
Sava: What you found is Bolbitius titubans (=B. vitellinus) in a mature stage where it does not show its bright yellow color and viscid cap. Your Conocybe guess was not far off. The two genera are similar. Conocybe are not viscid and (I believe) don't have striate caps.
Learning characteristics of genera and differences between them is a process which I have not mastered myself. For you and others interested, I would recommend the book "How to Identify Mushrooms to Genus VI: Modern Genera" by David L. Largent and Timothy J. Baroni. No pictures there, but an honest effort to give accessible descriptions of genera and the differences between the closely related ones.
