n 1823 the proposal was voted down 56 to 46. However, one of Symmes's followers, Jeremiah Reynolds, continued to lobby congress and was instrumental in obtaining funding for the 1838 Wilkes Expedition to the Antarctic and Seaborn's island, which was unsuccessful in obtaining passage to the lands of Symzonia. Official interest in further attempts to establish a route to Symzonia would not be re ignited until further evidence of the potential of such a passage could be shown.

s a follow up to Seaborn's expedition, McBride submitted a proposal to congress requesting that the U.S. government fund an expedition led by Symmes to the earth's interior. Symmes had claimed "I engage we find warm and rich land, stocked with thrifty vegetables and animals if not men, on reaching one degree northward of latitude 82; we will return in the succeeding spring."

he discovery of an extinct woolly mammoth frozen in ice in Siberia in 1846 was sited by Marshall Gardner as physical evidence of a habitable hollow earth. Gardner subscribed to the Euler single sun theory and suggested that the mammoth's well-preserved body was evidence its recent death. Gardner purposed that mammoths and other creatures now extinct on the outer surface wandered freely in the interior of the Earth. Explaining that the specimen had wandered outside by way of the hole at the North Pole, then succumb to the cold, frozen and carried to Siberia on an ice flow.