Ed Simpson, chairman of physical sciences at Kutztown University, talks about very early geology as early as 400 years ago.

He came to the Lehigh Gap Nature Center on Feb. 23 as part of its Speakers' Series.Simpson has traveled to Australia, South Africa, California, Utah, New Mexico and Pennsylvania to research trace fossils. Trace fossils are those with footprints or small insects captured in mud that became rock.One of the most prolific of sites was the red rock near what is called Marshalls Hill outside Palmerton.Dave Philmont, after retirement, came to Simpson and said he wanted to help Simpson's research. They went to the Reading Museum where he was introduced into the world of rocks. Many of the rocks in this area were shed by the rock walls along the Schuylkill Expressway, Philadelphia.To the west was an ocean called the Appalachian basin. The Mississippian epoch was 345 million years ago and was followed by the Silurian, the time of red rocks, the beginning of plants and early insects. Fish and amphibians began to be found in the coal regions and trace fossils were left behind.Isaac Lea and Sir Charles Lyell came to Pottsville in the early 1800s and examined rocks. Simpson had to use paintings to determine where they had been since it was too early for photographs. Some of the rock fossils they found are at the Academy of Science in Philadelphia complete with labels.Simpson and Philmont found an original cast of one of these rocks that came from behind a Pottsville hotel, no longer in existence. It was in the Smithsonian.Near the Tumbling Run Reservoir they got permission to search and brought out 250 slabs of rock. Some had dots which were insects and activity could be seen as they moved and the number of legs counted. Raindrops left impressions in the mud that became rock.A toad footprint is 6 inches across and from that it was determined the amphibian must have been three-feet long. Dragging tails left a trail in the rock.Fern fossils were found during the Silurnian period. The oldest organisms on land were believed to be in Pennsylvania, but that has been challenged.The red rocks on Marshall's Hill are in a band toward Port Clinton. Along it trace fossils are found.The geography of the land was of a broad, flat plain with shallow river systems and small fern-like bushes. The largest mountains were 7,000 to 8,000 feet tall.Early worms began to appear. Animals that were spider like, scorpion like and beetle like were evolving. Soft insects bored into the ground and created good soil.Simpson said people get confused about the difference between geologists and archeologists. "We have no power to shut down a construction site as an archeologist might," he said.There are many more fossils in the ocean because of a lack of oxygen. The land-based oxygen destroys them more quickly.Tectonic plates strike and pile up on each other creating the mountains instead of slipping and causing earthquakes.Traveling west closer to the Appalachian basin soft coal is found, which is 93 percent pure carbon. This area's anthracite coal cooked off the volatiles, leaving much purer 99 percent carbon coal which was cleaner burning.The oldest rocks in Pennsylvania are found near the Pagoda at Reading.