Sugarloaf Mountain and Urca Hill Natural Monument Mountain, then an island, on 1 March 1565. The site was chosen to guard the entrance to Guanabara Bay, and the mountain was important as a signalling point. A landfill connected the island to the mainland in 1697, and various buildings were erected to defend the territory, but the Urca urban neighborhood was only built 300 years after the city was founded. The Sugarloaf Mountain and Urca Hill Natural Monument was created by the city of Rio de Janeiro by municipal decree 26578 of 1 June 2006. The objectives are to guarantee green spaces for leisure in a natural area,
Sugarloaf Mountain (Massachusetts) type locality for the Mt. Toby Conglomerate, can be seen directly across the Connecticut River from Sugarloaf Mountain. About 200 million years ago, as the continent of North America began rifting apart from Africa and Eurasia, a series of erosion and deposition episodes interspersed with basalt lava flows created this layer cake. Faulting and earthquakes tilted the layers; subsequent erosion and glacial activity exposed the tilted "layers" of sandstone, basalt, and erosion-resistant conglomerate visible today. Although not composed of basalt trap rock, Sugarloaf Mountain is a closely associated with the Metacomet Ridge by virtue of its origin via the same