Writing retreats are known as quiet spaces for contemplative labor—but convening  poets, journalists and authors also tends to generate engaging conversation. This observation led to Conversations on the Edge, a series of informal public talks established by the Mesa Refuge, a writers’ retreat in Point Reyes Station. On Sunday, September 13, the refuge will host a conversation on the topic of the environment from 3 to 5 p.m. The dialogue features Jason Mark, a writer…