"Piedras Geodes" y nodulos silúricos en el Aparato para la Historia Natural española (1754) de José Torrubia

Abstract

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 «little cakes and diceboxes», considering them as petrefacts of nonorgan ic origin. The presence of nodules in Silurian graptolite facies in several i be rían localities is also briefly examined, and the diverse popular interpretations of these structures in the country are also annotated (i.e. «moorish heads», mammut-coprdlites, turtles or even «copro/ithus neanderthalensis»