FOREWORD 



from the Chief 



Not until 1951 did Robert Kosanke of the Illinois State Geological Survey discover fossils of 

 the Botryococcus alga in several Illinois coals, even though for a half century fossil algae had 

 been reported in coals worldwide. 



In 1963, Dr. Russel Peppers arrived at the Geological Survey and began his career-long 

 study of the fossil pollens and spores in coal. In his studies of thousands of coal samples, 

 Peppers kept Kosanke's discovery in mind and began collecting samples that contained this 

 particular alga. At last count, he had 43 samples of coal from widespread coal seams in 

 Illinois, Indiana, and Kentucky. 



In this report, Peppers and his colleague Dr. Richard Harvey, an expert in the description 

 and classification of coals and coal macerals, summarize their investigation into the fossil 

 algae in these 43 coal samples. Peppers and Harvey found that the alga occurs in 12 Illinois 

 coal beds. Their data on the distribution of Botryococcus in coal may help geologists identify, 

 correlate, and map coal seams across the Illinois Basin. 



The presence of the alga in a coal or shale can tell us about the changing environments of 

 the ancient swamps that covered Illinois about 315 to 310 million years ago. Peppers and 

 Harvey compared the distribution of Botryococcus with that of the spore assemblages in their 

 samples; they found that the alga is most abundant in layers in which Lycospora are most 

 abundant. Botroyococcus lived in freshwater, and this association reinforces previous evi- 

 dence that lycopod trees grew in wet and periodically flooded swamps. 



Peppers and Harvey also found the alga in layers of shale that originated as mud in 

 freshwater swamps. Where seawater covered the swamps and decomposing plants, there is 

 likely to be high-sulfur coal. Because freshwater shales commonly lie directly over low-sulfur 

 coal, finding shales with significant amounts of the Botryococcus alga may help geologists 

 locate deposits of low-sulfur coal. 



As with most research, this study raises new questions just as it is answering the ones the 

 scientists began with. The alga Botryococcus is still living today unchanged for over 400 

 million years. But it is not found in any Illinois coal beds above the lower Middle Pennsylva- 

 nian (about 310 million years ago), even though it is found in coals from other locations. Why 

 the disappearance? And even though the fossil algae were buried in coals thousands of feet 

 deep for millions of years, the cell bodies weren't flattened or coalified. Why not? These are 

 indeed intriguing questions for further investigation. 



William W. Shilts, Chief 

 Illinois State Geological Survey 



