Brazilian Amazônia. Sandstone, high on the river bank--Rio Braco Norte, at the air base. Serra do Cachimbo. Base Aérea do Cachimbo and vicinity; km 780-820 on Cuiabá-Santarém highway (BR 163); ca 20 km N of border of Mato Grosso. Low ridges and valleys to the N and S., Pará, Brazil, South America - Neotropics