In the 1840s and 50s many old buildings were replaced by larger business structures. Built from red sandstone, granite, and iron, the buildings varied in designs including Greek Revival, Gothic, and Italianate. One of the tallest buildings was the eight-story Jayne Building. Designed by William L. Johnston, the building had a Venetian Gothic façade and an observation tower designed by Thomas U. Walter. The Jayne Building was completed in 1850 and demolished in 1957. The city's first entirely cast-iron building was built in 1850. Built for Penn Mutual Life Insurance Company, the building was designed by G. P. Cummings.