This is Throwback Thursday #339. In these, we look back into the past at ESCONI specifically and Earth Science in general. If you have any contributions, (science, pictures, stories, etc …), please send them to esconi.info@gmail.com. Thanks!

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For today, we have an article written by Billy Kelly for the October 1955 edition of the ESCONI. Bill wrote many articles for the newsletter over the years. He and his wife Wylma were very generous with their time. They went on many field trips, including this one to Silvania, OH in 1959 (see Throwback Thursday #33).

I like this photo of Bill in the water looking for fossils at Sylvania.

This is Bill and Wylma in Houghton, MI at the Midwest convention in 1966. Wanda Boush sent this photo in for ESCONI’s 25th Anniversary in 1974.

Here’s is “The Rocks We Live On.”

“THE ROCKS WE LIVE ON”

If you go to Downers Grove High School at 8:00 PM on October 14, you will see hundreds of people buying rocks. They will buy rocks for dimes and dollars. They will also talk rocks, and the noise and excitement may astonish you. There will be a lecture on rocks. You had better go early, as there will be a crowd. This is the ESCONI annual auction sale of minerals, fossils, ores, jewels and rocks.

These are your neighbors and friends Boys, Girls, Men and Women and they are Rock-Hounds. This is a hobby and these people are playing at it and working at it. Many of them are now and will become mineralogists, geologists, archaeologists, paleontologists, astronomers or lapidaries. The geologists are just rock-hounds that get paid. The value of this hobby lies in the rocks you meet and the people you meet. There are rock-hounds wherever you go. You learn to spot them by some bragging stone they wear, and because they look around and see the landscape. They watch the sky, they see the earth, they walk on, and every once in a while they bend over and pick up a rock.

There is no such thing as an ordinary rock, We soon learn to distinguish the three main classifications, igneous, sedimentary, and metamorphic or altered rock. Then we have looked at rocks for a little while, we develop a sense of time and place. The time it took to develop the rocks and how they came to be in the place we find them. The record is in the rock; we can learn to read some of the record. It is not all clear and we will sometimes be mistaken, but we will learn about time and place.

Here in the middle west we are in glaciated country. The features of this land we live in were formed by the great ice sheets of the Pleistocene Period. The surface of earth was scraped bare down to the Laurentian Shield in the north and the ancient sedimentaries in the middle west to the Ohio River, and the Missouri River which marks the farthest advance of the glaciers. The surface material in this region was bull-dozed into its present place by the Ice Cap. The lakes, both great and small (except Superior which was a stationary mass of ice in a geosyncline or great trough) the rivers including the Mississippi Missouri and Ohio are glacial Features. We also have gravel pits and banks, Eskers, Moraines, Drumlins, Ketties, and drainage patterns that are of glacial origin, The important glaciated exposures of the ancient sedmentaries of the Paleozoic Era reveal coal at strip mines and Dolomite at the quarries for roads and concrete. Our bridges and tall buildings are based on these same sedimentaries.

The fertility of our farm lands where the tall corn grows is also due to great quantities of loess, which was air-born material carried from the west during periods of great storms across the denuded land as the glaciers retreated.

There were many advances and retreats during this most recent glaciation covering an estimated 20 million years. This includes five interglacial times. We may now be in the warming cycle of an inter-glacial time and none of the rock-hounds here present are going to know for sure, The last lobe of ice (Wisconsin lobe) retreated 10,000 years ago.

Below the replaced surface material, there lies a great deposit of Silurian Niagara Dolomite. This sedimentary rock is three to four hundred feet thick and lies exposed in many places.

The Silurian Seas inundated most of the North American continent several times, 300 to 370 million years ago. The sediments in these seas, soft, limey muck with shells of coral polyps, sponge skeletons, chitinous trilobites and hundreds of thousands of other sea animals formed a layer of calcium carbonate and silicon dioxide from sand and precipitation from the sea waters. A further alteration took place as precipitation of magnesium carbonate took place. Then great ages of time and tremendous pressures completed the formation of Dolomite, the hard rock we build with.

“THESE ARE THE ROCKS WE LIVE ON”

Bill Kelly