Thanks, Marvin. A great report that all cave diggers will love!
Lee Skinner
On 6/5/2022 10:00 AM, texascavers-requ...@texascavers.com wrote:
Date: Sat, 4 Jun 2022 21:14:11 -0500
From: Marvin Miller<cave0mil...@gmail.com>
To:Texascavers@texascavers.com
Subject: [Texascavers] Dinosaur Cave
Message-ID:
<CAF-yGDz21F4TxP1rh_vidyN3-P7OAw1oHVtCDXEPnY0rOd2L=g...@mail.gmail.com>
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Kelsey Dennis and Mio Kitano joined me today to finish up a little bit of
muddy survey and to push leads in Dinosaur Cave. Dinosaur Cave is a 642
meter-long cave in Comal County. The survey went about 2 meters down a hole
that had been too tight for the previous survey team. Both Kelsey and Mio
have slight figures ideal for these kinds of leads. The next survey shot
was 3 meters through a muddy trough into a small terminal room with some
drops falling from the ceiling. The drops had been a trickle when I had
first seen this room last year. The room isn't really terminal because
there is a slot in the floor that could be enlarged to get down to the next
little space 2 meters below but then there is another, tighter
constriction. There is no airflow so this is not a high priority lead.
We struggled out of these muddy confines and headed back towards the
entrance till we stopped at a hole that dropped down in the middle of the
passage. This hole leads to a bit of walking passage in the breakdown that
makes up the floor and fills the lower part of the main passage. 10 meters
along the breakdown passage a small hole in the floor drops down into a
small room, the floor of which slopes further down to the opening of a
small, horizontal tube in bedrock. The tube is straight and clean-washed
and can be seen to extend at least 5 meters. The tube is intimidating (to
me, at least) because it looks barely larger than body-sized. Once you get
into it there is actually a little more space than that, and only one spot
where you are scraping floor and ceiling. At about the 5-meter mark you
encounter a cross-joint which provides some relief, and immediately after
that the floor drops down into a fissure and then the passage widens, opens
up to the right, and drops over a ledge into a small room. Bennett Lee
pushed this passage and discovered this room. A small trickle of water
falls from a too-small tube in one wall. At floor level a duck under the
ceiling leads to a short 5-meter section of passage, at the end of which
was today's objective. At that point the floor trends slightly down and the
ceiling comes down to within 20 cm of the floor, which is clean-washed from
that point. I had tried to cram myself into this lead when Bennett, Greg
Mosier, and I surveyed the preceding passage but it was a no-go. I couldn't
even get far enough to see around the near corner. Kelsey is a skinny girl
and had no problem with it. There is a pool in the floor just after it gets
tight so she had to consider whether she wanted to get wet, but in the end
she committed to it and soon disappeared around the corner. She kept a
running commentary and informed us that just ahead it was going to open up
to walking - or at least stoop-walking height. She was soon there and
continued, sometimes in several cm of water. There was another short
constriction to be passed and then the passage dimensions resumed. She had
to stop, probably about 20 to 25 meters along, due to a boulder that was
filling the passage. She could see the passage continuing past the boulder.
Her assessment was that it could probably be broken up with a sledge or
rolled out of the way. There is good airflow coming out of this passage,
really the only airflow we have seen anywhere in Dinosaur Cave.
When Kelsey came back out, excited by her discovery, we set to work on the
other passage that exits here, stacked almost right on top of the water
crawl below. The problem with this one was that it was almost filled with a
2 meter-long, 1 meter-wide slab of breakdown. It wasn't very thick so we
had some hope that we could break it up somehow. We took turns beating on
the near end, and some bits broke off easily, but then it got hard. I
decided it was time to employ the hammer drill and straws. I had barely
drilled 4 cm into the rock when my bit got stuck and would not move. The
only way to rescue it was to beat on the rock some more. I started in on
that and suddenly the rock broke across its width about half-a-meter back.
This large chunk fell to the ground in front of the lower passage, and the
remainder of the slab started to slide down what must have been a slight
slope towards us! Fortunately, it stopped moving after 10 or 15 cm. We then
had a discussion that if a survey team was going to come back and attack
the lower passage, the slab would first need to be eliminated. We continued
pounding on it - with some care to have an escape route - and eventually
were able to lever it and chock it in a more stable situation. What all of
that ended up doing for us was open up space over the top of the slab to
crawl across and see what lay beyond. A quick look showed that the passage
took a sharp right turn and followed the trend of the lower passage. Mio
ventured in and I noticed that I could see a reflection of her light on the
pool in the lower passage. There were holes in the floor. In fact, she
remarked that the floor was not stable and there was a danger of falling
through. Several rocks were dislodged and fell into the lower passage.
About 4 meters in, the passage was blocked by flowstone, but she could see
around it into a larger space. It is almost certainly the same passage that
Kelsey traversed. This is a possible bypass to the lower level
constriction.
The new discovery is at the lowest point of the cave and the air was not
very good. We will wait until winter to organize further survey trips. We
left the cave happy, muddy, and tired.
Marvin Miller
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