Fascinating geology can be found up Convict Creek canyon above Convict Lake, California.  The trail leads one to Mildred Lake & the high basin below Red Slate Mountain in the Sierra Nevada.  The high cliffs are a mix of folded rock strata w/ dark gray limestone containing abundant fossil crinoid stems.  The trail can be hard to access at this point due to a footbridge being washed out at the intersection of two raging creeks.  Convict Creek below flows under some leftover snow patches.