Torrubia (7754) was the first to describe the presence of nodules in the Silurian black shales cropping out in the old tile works near El Pobo de Dueñas in the province of Guadalajara. He called then "geode-stones" reminiscent to "little cakes and diceboxes", considering them as petrefacts of nonorganic origin. The presence of nodules in Silurian graptolite facies in several Iberian localities is also briefly examined, and the diverse popular interpretations of these structures in the country are also annotated (i.e. "moorish heads", mammut-coprolites, turtles or even "coprolithus neanderthalensis").

3 páginas, 3 figuras.-- Trabajo presentado en la 21ª Sesión Científica, Huelva 1996.

Peer reviewed