Resumen de "Piedras Geodes" y nódulos silúricos en el Aparato para la Historia Natural española (1754) de José Torrubia
Juan Carlos Gutiérrez Marco, Isabel Rábano Gutiérrez del Arroyo, M. Bombín Espino, A. García Palacios, Pedro Herranz Araújo
Torrubia (1754) 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 them "geode-stones" reminiscent to "litle 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, tutles, or even "coprolithus neanderthalensis").
