, it led to alled these labor laws and without this, proving all these people wrong, we won't have the safety laws that we did today. >> thank you all very much. wrecks we continue want to the museum of the rockies where we see the fossil discoveries in montana. wonderful place for discovery of dinosaur fossils, not only because of the rock's that we have here and were present in the state, but also because they are exposed. the entire eastern portion of the state is exposed rock which preserves a lot of the most famous formation for dinosaurs is the

creek formation. it preserves the last of the dinosaurs and it out crops here in montana. we have a lot of formation in the state. finds where we go to triceratops and t-rex. these dinosaurs are known from the formation. this goes back to the native american days. this was during some of the classic bone wars. this is for the smithsonian or jail. 70'ssn't until the late

when we found a site thanks to landowners that were rockhounds in northern montana. when a family found the fragments of baby dinosaur bones. discoveries. prior to that, science on the dinosaurs rely crocodiles and alligators that they would lay there a and peace out -- lay their eggs and peace out. but these nesting's along with , we put the museum of the rockies on the map. it is focused on the fossils from the hell creek formation.

the last non-avian dinosaurs that went extinct, they are 66 million years ago. is because of two types of dinosaurs in particular that i bet you've heard of. that is treasurer tops which is the horned dinosaur. and the tea comes from t-rex. has produced a number of phenomenal to read a saurus wrecks behind me here. quite the fearsome predator, as you can see. so the dinosaur behind me does have a name. we do have a couple of other names. the success and a number is in lower 980. the t-rex was discovered on the fourth of july in the late 90's which i would love to share it

is a very patriotic dinosaur. why are you working on the fourth of july? why would you think that that's work? this is fun. it wasn't the museum, it was local true to found montana's the newd then contacted zealand the rockies to help with that excavation. the skeleton of the t-rex standing behind me is more than 16% real bone. and that is the difference you see behind you. the darker colors represent the actual bone. fromrepresent the replica other t-rex is to make him complete. that is 100% complete.

this in front of you is a rare and spectacular opportunity. the triceratops we have mounted as well. had a little one on the i and a smaller one on the nose. favoritekely to be a prey item of t-rex. we find quite a bit of concern tops material with bite marks or t-rex teeth in the dinosaur. they can avoid t-rex as much as possible.

behind me here, these are all different skulls from triceratops which is a horned dinosaur. they are called triceratops because the have two horns above their eyes. the most commonly found dinosaur in the creek formation. the benefit of being such a commonly found dinosaur is that we can say a lot about how triceratops grew and developed through its life.

can see the smallest triceratops skull to ever be discovered. it is still quite itty-bitty. we start to see the horns above the eyes get bigger. on the back of the frail, we call those triangles the epi-o ccipitals. they fuse later and later. you can see in the teenage that their horns are more bigger and curved. throughontinue on getting closer and closer to adulthood. these triceratops would have been sexually mature. here we see the largest of our two in the growth series.

and you can see the shift that the horns have gone from pointing upward to pointing down instead. this may have to do a species recommendation -- species recognition, telling the adults from the juveniles. these holes that developed in the back of the frills. these would not have been holes in life but covered with skin. they are deposited on the bigger horns on the facial region. this is in the front of the face. ,ow we know all of those things

that this is an older triceratops and not a different species is because of bone histology. using a research method to tell the age of individuals. it is when you slice up in animals bone, a fossilized dinosaur bone and you slice it so thin that you can put it on a slide and look at it under a microscope. look at the microscopic network of that bone. it gives us an idea of the relative ages of the long extinct giants. a growthdo we have series, but we have the largest t-rex in the world as well. i call this area the t-rex fishbowl. you can see the smallest t-rex

skulls ever discovered. with thel one is researcher and being studied right now. it is from montana. we have another juvenile and a younger t-rex. so those are your younger t-rex is -- younger t-rex's. there has been debate about if it is a different species or a juvenile t-rex. here, through the study of histology, we are confident in our hypothesis that these represent juvenile t-rex's. a sub-adult v-rex, t-rex. he has an incredible story largely due to the resort -- research of dr. mary schweitzer.

research found the oldest traces of soft tissue to ever be preserved. an incredibly important scientific specimen that has changed what we know about dinosaur soft tissue and dinosaur biology. as we round the corner, we see larger and larger t-rex. skull of thethe montana t-rex for you to see up close and personal. this is now the actual specimen, the centerpiece of the smithsonian deep time exhibit. excited thaty

t-rex is on the center stage in washington dc. d.c. hington, and this is one of the largest skulls to be discovered, ever. this is more than five feet in huge. and would have been the skeleton was much larger. it was one of the highlights.

this gives visitors the opportunity to see them working on fossils right there in front of them, and the volunteers that work here in the viewing lab. how we get them out of the field. we can see a different variety of dinosaur bones being prepared. femur in triceratops the works. it needs to be consolidated quite a bit. it is still in the field jacket which is made out of plaster and burlap. the upper leg bone of a triceratops dinosaur. a fairly good-sized one at that.

next to it, we have a triceratops vertebra. we have an individual backbone. it works fairly well together. we are working on it. how long have you been here? >> six years. over 5000 hours that levi has volunteered and donated to be here in the viewing lab.

levi is very skilled. we are proud to show how proud we are of our volunteers and to share the process of paleontology with our visitors. think it is extremely important to have small, regional museums like the museum of the rockies fairly large such as the smithsonian museum. i think those are important because they preserve our nation's history. -- it isinct really actually important to have the museum of the rockies and get pulled back.

>> to watch more video, visit c-span.org/citiestour. [captioning performed by the national captioning institute, which is responsible for its caption content and accuracy. visit ncicap.org] [captions copyright national cable satellite corp. 2019] >> each week, american artifacts takes you to museums and learning about american history. karen sherry focuses on sharing stories that individuals that led to slave revolts. >> will come to the virginia museum of history and culture in richmond, virginia.