One of many
trip reports under the
SilGro home page for Alan Silverstein and Cathie
Grow.
Email me at
ajs@frii.com.
Last update: March 29, 2024
(Previous trip report: 2005_0713-22_BlueForestWyoming.htm)
Adapted from email I sent:
From: Alan Silverstein <ajs@frii.com> Date: 27 Sep 2006 12:51:09 -0600 Subject: Re: [Rockhounds] Fall Fieldtrip Reports To: rockhounds@lists.drizzle.com
"...how about the rest of you... any other fall fieldtrip stories out there?"
OK since you asked... A few days ago on Sunday, I got a chance to visit Grays Quarry in Wyoming for the fourth time (along with others from the Fort Collins rockhounds club). This was a large limestone quarry on private property (the Grays were local ranchers) about seven miles north of Glendo, in east-central Wyoming.
The quarry was cut into the southwest side of a hill on the west bank of the North Platte River. The hill was perhaps 200' high, and the quarry highwall was 100-150' high at points (although terraced). The limestone was heavily altered by silicification, and it featured a mind-numbing variety of colorful druzy quartz coated vugs, agates, and jaspers.
(Incidentally, much of this same type of material can be found at many local highway outcrops or around Glendo Reservoir.)
From Fort Collins, Colorado, the drive was about 155 miles and 2+ hours one way. I'd hoped to head up Saturday morning with a kayak, camp on the north bay of Glendo Reservoir, and spend the afternoon collecting solid, pretty vein agates (up to 3" or so thick) on the shorelines, which was legal with prior notice to the state park.
Unfortunately we had a couple of pre-winter cold fronts arrive Wed-Fri, and the weather Saturday was cold and wet. Worse, the lake had dropped 40' since I was last there in June, and calling ahead, I learned there was no longer a north bay! I gave up and just did a day trip to the quarry. Sunday morning I could see that the north bay was now mile-wide mud flats with a trickle of river running through it, and cows munching on vegetation on the drier parts.
But the Sunday weather was excellent, with fog remnants milling about the Platte valley as we arrived at about 10:15 in Glendo and about 10:45 at the quarry. There were six vehicles and about 15 people in our small group, following the lead of the president of the Cheyenne club. The quarry floor was wet and muddy in spots! It apparently had rained overnight.
Some of us stayed until 6 pm (local sunset 7 pm) digging, busting up boulders, and/or surface collecting. It was sunny, cool to warm, and breezy to windy at times -- which is fair weather in Wyoming!
Every time to the quarry the terrain was different as they blasted and hauled rubble to the crushers for roadbuilding. This time I didn't luck into any great vugs or veins, unlike the previous three trips, but still brought home about eight 3-gallon buckets of material to sort, ranging from display pieces to tumbling material.
I did try digging one hole into shattered bedrock, and it was easy to take apart as usual, but this particular location yielded only white to yellow mini-botryoidal coatings, no blue/purple druzy (the real prize) and/or calcite crystals (dogtooths, or masses up to inches across). In another spot I could only find rubble, no bedrock. I spent a lot of the time surface-collecting over the top of the hill with friends.
(Next trip report: 2006_1103-05_FallWeekend.htm)