Officers seized 350 mature marijuana plants last Thursday on private property abutting Walker Creek near Tomales, according to the Marin County Sheriff’s Office. The grow site sported useable bud worth $700,000 in street sales, and officers also found 100 pounds of fertilizer, some of which was spilling into the stream from bags left in the creek bed. The long-term impacts of the fertilizer spill are “intangible,” Lieutenant Doug Pittman said in an email, but sheriffs…