This is the fourth in a five-part series on the stories that had the greatest impact during 2014 in the Ellwood City area. Previous installments covered the winter of 2013-14, the acquisition of ESB Bank by WesBanco, and violent crimes in the Walnut Ridge public housing complex.

In early October, the Great March for Climate Action crossed the Ohio-Pennsylvania state line in Lawrence County, with the route selection determined at least partly because of Marcellus shale drilling.

The climate marchers, who had begun their trek in March in Los Angeles and finished it last month in Washington, D.C., were protesting natural gas extraction and injection well storage of waste products from drilling in the Youngstown area. Marchers bunked down for the night of Oct. 10-11 on the North Beaver Township farm of Maggie Henry, who had joined the climate change activism movement after a Marcellus natural gas well was put in near her farm.

For good and ill -- which is how Henry characterizes it -- the Marcellus shale revolution grew during 2014 in Lawrence County, which sits almost centrally in the Marcellus play. The Marcellus shale level, which runs underground from central New York through northwestern Pennsylvania, eastern Ohio, western West Virginia and into Kentucky, contains what analysts believe to be massive amounts of trapped natural gas.

In the last 10 years, drilling companies have begun using horizontal drilling and hydraulic fracturing, also called fracking, to extract the natural gas from the Marcellus layer. Fracking is the use of high-pressure liquids and sand -- to crack the shale and release the natural gas.

Over the past four years, the presence of Marcellus drilling has increased, with Lawrence County property owners obtaining drilling leases with upfront payments into six figures. Among the property owners receiving badly needed funds was the borough of Ellwood City, which agreed on a lease on public property that enabled it to spend more than $100,000 for refurbishing its swimming pool.

Marcellus shale also played a role in the region's largest business transaction of 2014 -- the acquisition of ESB Bank by WesBanco. At the time it was announced, a WesBanco official said the takeover of ESB would increase the banking firm's footprint in the Marcellus region.

Lawrence County also stands to benefit if Shell follows through on its plans to build a natural gas refinery called a "cracker" plant. The cracker plant, proposed for Beaver County, would probably employ Lawrence County residents as well.

Analysts expect that 10,000 construction workers would be needed to build it, and it would employ about 400 people, with energy industry analysts estimating that another 10,000 jobs could be created in related businesses or commerce.