Expertise abroad

In 1841 the Lyells traveled to the United States for the first time. Lyell delivered a series of lectures at the Lowell Institute in Boston and explored the geology of the Atlantic coast. He was not a polished lecturer, but his engagements were always filled to capacity with those interested in his vision of the planet in ancient times. While touring North America he estimated the rate of recession of Niagara Falls toward Lake Erie, studied the Tertiary formations on the coasts of Virginia, the Carolinas, and Georgia, explored the Ohio Valley, Lake Erie, and Lake ontario, examined coal in Nova scotia, and visited an earthquake site in New Madrid, Missouri. In 1845 he published Travels in North America, then returned to deliver the Lowell lectures, explore the south including the coalfields in Alabama, investigate the growth of the delta of the Mississippi River, and collect fossils. After publishing A Second Visit to the United States of North America (1849), he returned again in 1852 and 1853.

Lyell traveled to Madeira and the Canary Islands in the Atlantic Ocean from 1853 to 1854 to study volcanic geology. Buch had proposed the craters of elevation theory to explain the formation of volcanic islands such as Tenerife and Palma (of the Canary Islands). He thought that volcanoes were formed by the horizontal solidification of lava, followed by violent upheaval incomparable to any modern-day geological processes, and then the collapse of masses of Earth, forming tentlike roofs over large conical caverns. From his visit to France in 1828 Lyell recalled the intact cones and craters of extinct volcanoes and the unbroken sheets of lava extending from the cones in the Auvergne. In 1859 Lyell again visited the sheets of hardened rock on the slopes of Mount Etna and Mount Vesuvius in Italy and found no center of upheaval as would be predicted by Buch's proposed mechanism. In addition he had seen modern lavas solidifying on 15-20 degree angled slopes on Madeira and Palma. On Etna he witnessed lavas solidifying on slopes of up to 40 degrees. In 1858 he published "On the Structure of Lavas Which Have Consolidated on Steep Slopes; With Remarks on the Mode of Origin of Mount Etna, and on the Theory of Craters of Elevation," a paper that invalidated the theory of craters of elevation.

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